Academic literature on the topic 'Primordial follicles'
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Journal articles on the topic "Primordial follicles"
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Kezele, Phillip, and Michael K. Skinner. "Regulation of Ovarian Primordial Follicle Assembly and Development by Estrogen and Progesterone: Endocrine Model of Follicle Assembly." Endocrinology 144, no. 8 (2003): 3329–37. http://dx.doi.org/10.1210/en.2002-0131.
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Abstract The assembly of the developmentally arrested primordial follicle and the subsequent transition of the primordial follicle to the primary follicle are critical processes in normal ovarian physiology that remain to be elucidated. Ovarian follicles do not proliferate and the primordial follicles present in the neonate represent the total number of gametes available to a female throughout her reproductive life. The primordial follicles are oocytes surrounded by less differentiated squamous granulosa cells and are derived from oocyte nests, and primary follicles are oocytes surrounded by a single layer of cuboidal granulosa cells that have initiated follicle development. Abnormalities in primordial follicle assembly, arrest, and development (i.e. primordial to primary follicle transition) can cause pathological conditions such as premature ovarian failure. In this study newborn rat ovaries were cultured for 7 d. The rate of primordial follicle assembly in vivo was identical with the rate in vitro. Interestingly, the rate of primordial follicle transition to the primary follicle was found to be 3 times greater in culture. This abnormal rate of primary follicle development in culture suggests the primordial follicle does not arrest in development as observed in vivo. To investigate this phenomena newborn rat ovaries were cultured in the presence of progesterone, estradiol or calf serum. Estradiol, progesterone, or calf serum significantly reduced the level of initial primordial to primary follicle transition. Approximately 60% of follicles make the primordial to primary follicle transition in control ovaries and about 30% in treated ovaries. Steroids and calf serum had no effect on the primordial to primary follicle transition in ovaries collected and cultured from postnatal 4-d-old rats, suggesting the effects observed are restricted to the initial wave of primordial to primary follicle transition. Interestingly, progesterone was also found to significantly reduce the rate of primordial follicle assembly. All viable oocytes assembled into primordial follicles in control ovaries and approximately 40% remained unassembled in progesterone-treated ovaries. Progesterone was also found to reduce primordial follicle assembly in vivo with 10% of the total follicles remaining unassembled in progesterone injected neonatal animals. Analysis of cellular apoptosis demonstrated that progesterone inhibited the coordinated oocyte apoptosis required for primordial follicle assembly. The hypothesis developed is that high levels of maternal and fetal steroids prevent premature primordial follicle assembly and primordial to primary follicle transition in the embryo. After birth steroid levels fall dramatically and the primordial follicles are free to assemble and initiate development. These observations suggest a novel role for steroids and the maternal-fetal endocrine unit in the control of ovarian primordial follicle assembly and early follicular development.
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Nilsson, Eric E., Chris Detzel, and Michael K. Skinner. "Platelet-derived growth factor modulates the primordial to primary follicle transition." Reproduction 131, no. 6 (2006): 1007–15. http://dx.doi.org/10.1530/rep.1.00978.
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Primordial follicles steadily leave the arrested pool and undergo a primordial to primary follicle transition during the female reproductive lifespan. When the available pool of primordial follicles is depleted reproduction ceases and humans enter menopause. The present study was designed to investigate the actions of several growth factors previously identified as candidate regulatory factors for the primordial to primary follicle transition with a microarray analysis. Ovaries from 4-day-old rats were placed into culture and treated for 2 weeks with platelet-derived growth factor (PDGF), anti-PDGF neutralizing antibody, vascular endothelial growth factor (VEGF), neuregulin (NRG), or kit ligand (KITL) as a positive control. PDGF-treatment resulted in a significant decrease in the percentage of primordial follicles and a concomitant increase in the percentage of developing primary follicles compared to controls. In contrast, ovaries treated with an anti-PDGF neutralizing antibody had a significant increase in the percentage of primordial follicles demonstrating an inhibition of endogenous follicle development. Ovaries incubated in the presence of VEGF or NRG had no change in follicle development. Observations indicate that PDGF, but not VEGF or NRG, promotes the primordial to primary follicle transition. Immunohistochemical localization indicated that the PDGF protein was present in the oocytes of both primordial and developing follicles. PDGF-treatment of cultured ovaries resulted in an increase in KITL mRNA expression. KITL has been previously shown to promote the primordial to primary follicle transition. KITL-treatment of ovaries had no effect on expression of Pdgf or any PDGF homologs or receptors. Therefore, PDGF appears to be produced by the oocyte and acts as one of several extracellular signaling factors that regulate the primordial to primary follicle transition. These observations provide insight into the cell–cell interactions involved in the regulation of primordial follicle development and can be used in the future development of therapies for some forms of infertility.
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Chen, Yu-Ying, Daniela D. Russo, Riley S. Drake, et al. "Single-cell transcriptomics of staged oocytes and somatic cells reveal novel regulators of follicle activation." Reproduction 164, no. 2 (2022): 55–70. http://dx.doi.org/10.1530/rep-22-0053.
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In brief Proper development of ovarian follicles, comprised of an oocyte and surrounding somatic cells, is essential to support female fertility and endocrine health. Here, we describe a method to isolate single oocytes and somatic cells from the earliest stage follicles, called primordial follicles, and we characterize signals that drive their activation. Abstract Primordial follicles are the first class of follicles formed in the mammalian ovary and are comprised of an oocyte surrounded by a layer of squamous pre-granulosa cells. This developmental class remains in a non-growing state until individual follicles activate to initiate folliculogenesis. What regulates the timing of follicle activation and the upstream signals that govern these processes are major unanswered questions in ovarian biology. This is partly due to the paucity of data on staged follicle cells since isolating and manipulating individual oocytes and somatic cells from early follicle stages are challenging. To date, most studies on isolated primordial follicles have been conducted on cells collected from animal-age- or oocyte size-specific samples, which encompass multiple follicular stages. Here, we report a method for collecting primordial follicles and their associated oocytes and somatic cells from neonatal murine ovaries using liberase, DNase I, and Accutase. This methodology allows for the identification and collection of follicles immediately post-activation enabling unprecedented interrogation of the primordial-to-primary follicle transition. Molecular profiling by single-cell RNA sequencing revealed that processes including organelle disassembly and cadherin binding were enriched in oocytes and somatic cells as they transitioned from primordial to the primary follicle stage. Furthermore, targets including WNT4, TGFB1, FOXO3, and a network of transcription factors were identified in the transitioning oocytes and somatic cells as potential upstream regulators that collectively may drive follicle activation. Taken together, we have developed a more precise characterization and selection method for studying staged-follicle cells, revealing several novel regulators of early folliculogenesis.
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Ruoss, Chantelle, Amanda Tadros, Tim O'Shea, Jim McFarlane, and Ghanim Almahbobi. "Ovarian follicle development in Booroola sheep exhibiting impaired bone morphogenetic protein signalling pathway." REPRODUCTION 138, no. 4 (2009): 689–96. http://dx.doi.org/10.1530/rep-09-0190.
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The role of bone morphogenetic proteins (BMPs) in the regulation of ovarian function has been extensively investigated but the mechanism of regulation is not well understood. The aim of this study was to investigate the effect of mutation in the BMP receptor in Booroola sheep on the number of primordial follicles and rate of follicle recruitment in comparison with that in normal merino sheep in vivo. Whole sheep ovaries at the time of birth, 1.5 and 5 years old were collected and processed for the follicle quantification, using computerised stereological methods and statistical analyses. At birth, the total number of primordial follicles in Booroola sheep was significantly lower than in merino sheep. At 1.5 and 5 years, a reversed pattern in favour of Booroola ewes was seen with significantly more primordial follicles than merino. In parallel, the rate of primordial follicle recruitment to developing cohort was substantially lower in Booroola ewes with only 51 and 66% of primordial follicle consumption at 1.5 and 5 years respectively compared to 92 and 97% in merino ewes. On other hand, the mean numbers of developing primary follicles were smaller in Booroola sheep at the time of birth, yet, Booroola ewes possess more primary follicles than merino at 1.5 years. These findings suggest that attenuation of the intraovarian signalling pathway of BMPs may in fact be a successful means of rationalising follicle consumption, preventing unnecessary loss of follicles from the initial primordial follicle pool, hence increasing reproductive longevity and fertility.
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Wang, Cheng, and Shyamal K. Roy. "Expression of E-Cadherin and N-Cadherin in Perinatal Hamster Ovary: Possible Involvement in Primordial Follicle Formation and Regulation by Follicle-Stimulating Hormone." Endocrinology 151, no. 5 (2010): 2319–30. http://dx.doi.org/10.1210/en.2009-1489.
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We examined the expression and hormonal regulation of E-cadherin (CDH1) and N-cadherin (CDH2) with respect to primordial follicle formation. Hamster Cdh1 and Cdh2 cDNA and amino acid sequences were more than 90% similar to those of the mouse, rat, and human. Although CDH1 expression remained exclusively in the oocytes during neonatal ovary development, CDH2 expression shifted from the oocytes to granulosa cells of primordial follicles on postnatal day (P)8. Subsequently, strong CDH2 expression was restricted to granulosa cells of growing follicles. Cdh2 mRNA levels in the ovary decreased from embryonic d 13 through P10 with a transient increase on P7, which was the day before the appearance of primordial follicles. Cdh1 mRNA levels decreased from embryonic d 13 through P3 and then showed a transient increase on P8, coinciding with the formation of primordial follicles. CDH1 and CDH2 expression were consistent with that of mRNA. Neutralization of FSH in utero impaired primordial follicle formation with an associated decrease in Cdh2 mRNA and CDH2, but an increase in Cdh1 mRNA and CDH1 expression. The altered expression was reversed by equine chorionic gonadotropin treatment on P1. Whereas a CDH2 antibody significantly reduced the formation of primordial and primary follicles in vitro, a CDH1 antibody had the opposite effect. This is the first evidence to suggest that primordial follicle formation requires a differential spatiotemporal expression and action of CDH1 and CDH2. Further, FSH regulation of primordial follicle formation may involve the action of CDH1 and CDH2.
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Watanabe, Ren, Sho Sasaki, and Naoko Kimura. "Activation of autophagy in early neonatal mice increases primordial follicle number and improves lifelong fertility†." Biology of Reproduction 102, no. 2 (2019): 399–411. http://dx.doi.org/10.1093/biolre/ioz179.
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Abstract The number of stockpiled primordial follicles is thought to be responsible for the fate of female fertility and reproductive lifetime. We previously reported that starvation in nonsuckling early neonatal mice increases the number of primordial follicles with concomitant autophagy activation, suggesting that autophagy may accelerate the formation of primordial follicles. In this study, we attempted to upregulate the numbers of primordial follicles by administering an autophagy inducer and evaluated the progress of primordial follicle formation and their fertility during the life of the mice. To induce autophagy, mice were intraperitoneally injected with the Tat-beclin1 D-11 peptide (0.02 mg/g body weight) at 6–54 h or 60–84 h after birth. In animals that received Tat-beclin 1 D-11 by 54 h after birth, the primordial follicle numbers were significantly increased compared with the control group at 60 h. The ratio of expressed LC3-II/LC3-I proteins was also significantly greater. The numbers of littermates from pregnant females that had been treated with Tat-beclin 1 D-11 were maintained at remarkably greater levels until 10 months old. These results were supported by an abundance of primordial follicles at even 13–15 months old.
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Al-Samerria, S., I. Al-Ali, J. R. McFarlane, and G. Almahbobi. "The impact of passive immunisation against BMPRIB and BMP4 on follicle development and ovulation in mice." REPRODUCTION 149, no. 5 (2015): 403–11. http://dx.doi.org/10.1530/rep-14-0451.
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The primordial follicle reserve is the corner stone of female fertility and determines the longevity and quality of reproduction. Complete depletion of this reserve will lead to primary infertility, and the key-limiting step of follicle depletion is the transition from primordial to primary follicles. It has been reported that this process is gonadotrophin-independent, but other conflicting reports are indicated otherwise and this discrepancy needs to be unequivocally clarified. The aim of this study was to investigate the role of bone morphogenetic proteins (BMPs) in the regulation of folliculogenesis in mice passively immunised against BMP receptor 1B (BMPRIB) and BMP4. While a stereological study revealed that the numbers of primordial follicles in immunised mice were significantly higher when compared with control animals, treatment with equine chorionic gonadotrophin showed no effect. In parallel, immunofluorescence microscopy revealed the presence of BMPRIB but not FSH receptor in primordial follicles. The number of primary follicles in immunised mice were also significantly increased when compared with control animals. After puberty, the rates of depletion of primordial and primary follicles were increased with age, particularly in treated animals; however, there was no significant difference between the treatment groups of the same age. Based on these results together with our previous reports in sheep and mice, we confirm that the attenuation of BMP signalling system can be an effective approach to sustain the primordial follicle reserve while promoting the development of growing follicles, ovulation and consequently overall female fertility.
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Wang, Cheng, та Shyamal K. Roy. "Development of Primordial Follicles in the Hamster: Role of Estradiol-17β". Endocrinology 148, № 4 (2007): 1707–16. http://dx.doi.org/10.1210/en.2006-1193.
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The role of E2 on primordial follicle formation was examined by treating neonatal hamsters with 1 or 2 μg estradiol cypionate (ECP) at age postnatal d 1 (P1) and P4 or by in vitro culture of embryonic d 15 (E15) ovaries with 1, 5, or 10 ng/ml estradiol-17β (E2). The specificity of E2 action was examined by ICI 182,780. One microgram of ECP maintained serum levels of E2 within the physiological range, significantly reduced apoptosis, and stimulated the formation and development of primordial follicles. In contrast, 2 μg ECP increased serum E2 levels to 400 pg/ml and had significantly less influence on primordial follicle formation. In vivo, ICI 182,780 significantly increased apoptosis and caused a modest reduction in primordial follicle formation. The formation and development of primordial follicles in vitro increased markedly with 1 ng/ml E2, and the effect was blocked by ICI 182,780. Higher doses of E2 had no effect on primordial follicle formation but significantly up-regulated apoptosis, which was blocked by ICI 182,780. CYP19A1 mRNA expression occurred by E13 and increased with the formation of primordial follicles. P4 ovaries synthesized E2 from testosterone, which increased further by FSH. Both testosterone and FSH maintained ovarian CYP19A1 mRNA, but FSH up-regulated the expression. These results suggest that neonatal hamster ovaries produce E2 under FSH control and that E2 action is essential for the survival and differentiation of somatic cells and the oocytes leading to the formation and development of primordial follicles. This supportive action of E2 is lost when hormone levels increase above a threshold.
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Dole, Gretchen, Eric E. Nilsson, and Michael K. Skinner. "Glial-derived neurotrophic factor promotes ovarian primordial follicle development and cell–cell interactions during folliculogenesis." REPRODUCTION 135, no. 5 (2008): 671–82. http://dx.doi.org/10.1530/rep-07-0405.
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Female fertility is determined in part by the size and development of the primordial follicle pool. The current study investigates the role of glial cell-line-derived neurotrophic factor (GDNF) in the regulation of primordial follicle development in the ovary. Ovaries from 4-day-old female rat pups were maintained in organ culture for 10 days in the absence (control) or presence of GDNF or kit ligand (KL)/stem cell factor. Ovaries treated with GDNF contained a significant increase in developing follicles, similar to that observed with KL treatment previously shown to promote follicle development. The actions of GDNF on the ovarian transcriptome were investigated with a microarray analysis. Immunohistochemical studies demonstrated that GDNF is localized to oocyte cytoplasm in follicles of all developmental stages, as well as to cumulus granulosa cells and theca cells in antral follicles. GDNF receptor α1 (GFRα1) staining was localized to oocyte cytoplasm of primordial and primary follicles, and at reduced levels in the oocytes of antral follicles. GFRα1 was present in mural granulosa cells of antral follicles, theca cells, and ovarian surface epithelium. The localization studies were confirmed with molecular analysis. Microarray analysis was used to identify changes in the ovarian transcriptome and further elucidate the signaling network regulating early follicle development. Observations indicate that GDNF promotes primordial follicle development and mediates autocrine and paracrine cell–cell interactions required during folliculogenesis. In contrast to the testis, ovarian GDNF is predominantly produced by germ cells (oocytes) rather than somatic cells.
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Silva, J. R. V., T. Tharasanit, M. A. M. Taverne, et al. "The activin-follistatin system and in vitro early follicle development in goats." Journal of Endocrinology 189, no. 1 (2006): 113–25. http://dx.doi.org/10.1677/joe.1.06487.
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The aim of the present study was to investigate the effects of activin-A and follistatin on in vitro primordial and primary follicle development in goats. To study primordial follicle development (experiment 1), pieces of ovarian cortex were cultured in vitro for 5 days in minimal essential medium (MEM) supplemented with activin-A (0, 10 or 100 ng/ml), follistatin (0, 10 or 100 ng/ml) or combinations of the two. After culture, the numbers of primordial follicles and more advanced follicle stages were calculated and compared with those in non-cultured tissue. Protein and mRNA expression of activin-A, follistatin, Kit ligand (KL), growth differentiation factor-9 (GDF-9) and bone morphogenetic protein-15 (BMP-15) in non-cultured and cultured follicles were studied by immunohistochemistry and PCR. To evaluate primary follicle growth (experiment 2), freshly isolated follicles were cultured for 6 days in MEM plus 100 ng/ml activin-A, 100 ng/ml follistatin or 100 ng/ml activin-A plus 200 ng/ml follistatin. Morphology, follicle and oocyte diameters in cultured tissue and isolated follicles before and after culture were assessed. Terminal deoxynucleotidyl transferase-mediated dUTP nick-end labelling (TUNEL) reactions were performed to study DNA fragmentation in follicles. In experiment 1, it was found that goat primordial follicles were activated to develop into more advanced stages, i.e. intermediate and primary follicles, during in vitro culture, but neither activin-A nor follistatin affected the number of primordial follicles that entered the growth phase. Activin-A treatment enhanced the number of morphologically normal follicles and stimulated their growth during cortical tissue culture. The effects were, however, not counteracted by follistatin. The follicles in cultured goat tissue maintained their expression of proteins and mRNA for activin-A, follistatin, KL, GDF-9 and BMP-15. Fewer than 30% of the atretic follicles in cultured cortical tissue had TUNEL-positive (oocyte or granulosa) cells. Activin-A did not affect the occurrence of TUNEL-positive cells in follicles within cortical tissue. In experiment 2, addition of activin-A to cultured isolated primary follicles significantly stimulated their growth, the effect being counteracted by follistatin. Absence of such a neutralizing effect of follistatin in the cultures with ovarian cortical tissue can be due to lower dose of follistatin used and incomplete blockage of activin in these experiments. In contrast to cortical enclosed atretic follicles, all atretic follicles that had arisen in cultures with isolated primary follicles had TUNEL-positive cells, which points to differences between isolated and ovarian tissue-enclosed follicles with regard to the followed pathways leading to their degeneration. In summary, this in vitro study has demonstrated that cultured goat primordial follicles are activated to grow and develop into intermediate and primary follicles. During in vitro culture, the follicles maintain their ability to express activin-A, follistatin, KL, GDF-9 and BMP-15. The in vitro growth and survival of activated follicles enclosed in cortical tissue and the in vitro growth of isolated primary follicles are stimulated by activin-A.
Dissertations / Theses on the topic "Primordial follicles"
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Dubbaka, Venu Pradeep Reddy. "Molecular studies of intra-oocyte phosphatidylinositol 3 kinase (PI3K) signaling pathway in controlling female fertility." Doctoral thesis, Umeå : Umeå university, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-26088.
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Ribeiro, Regislane Pinto. "Efeito da lectina jacalina (artocarpus integrifolia) sobre a sobrevivÃncia e ativaÃÃo in vitro de folÃculos primordiais caprinos." Universidade Federal do CearÃ, 2013. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=10620.
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FundaÃÃo Cearense de Apoio ao Desenvolvimento Cientifico e TecnolÃgicoOs objetivos deste estudo foram investigar o efeito de diferentes concentraÃÃes de jacalina e da interaÃÃo de jacalina e FSH sobre a sobrevivÃncia, ativaÃÃo e expressÃo gÃnica em folÃculos primordiais caprinos cultivados in vitro. Para isto, os fragmentos do cÃrtex ovariano foram cultivados em Meio Essencial MÃnimo (MEM) suplementado com diferentes concentraÃÃes de jacalina (0, 10, 25, 50 e 100 μg/mL - experimento I), por um e seis dias. ApÃs o tÃrmino do perÃodo de cultivo, os fragmentos de cÃrtex ovariano foram fixados para histologia clÃssica. Em seguida, avaliou-se a percentagem de folÃculos primordiais ou em desenvolvimento no controle nÃo cultivado e no tecido ovariano cultivado nos diferentes tratamentos. ApÃs a determinaÃÃo da concentraÃÃo de jacalina mais eficiente (50 μg/mL), realizou-se o cultivo de fragmentos de cÃrtex ovariano em MEM suplementado com a jacalina (50 μg/mL), FSH (50 ng/mL) ou ambos (experimento II). ApÃs 6 dias de cultivo, os fragmentos ovarianos foram fixados para histologia clÃssica. AlÃm disso, para cada tratamento, foram coletadas amostras de tecido para avaliar o perfil de expressÃo de RNAs mensageiros para BMP-15, KL, c-kit, GDF-9 e PCNA em folÃculos ovarianos caprinos cultivado in vitro por 6 dias. Os resultados demonstraram que apÃs seis dias de cultivo, a presenÃa de 50 μg/mL de jacalina no meio de cultivo promoveu um aumento de folÃculos morfologicamente normais, bem como uma reduÃÃo da percentagem de folÃculos primordiais e aumento de folÃculos em desenvolvimento, quando comparado ao meio controle. No experimento II, demonstrou-se que jacalina ou FSH estimulam a ativaÃÃo dos folÃculos e contribuem para a manutenÃÃo da viabilidade, mas nÃo foi observada uma interaÃÃo positiva entres essas duas substÃncias. A expressÃo de RNAm para a BMP-15 e KL apÃs o cultivo in vitro de fragmentos de ovÃrio nos diferentes tratamentos por 6 dias nÃo foi alterada. No entanto, a presenÃa de FSH aumentou os nÃveis de RNAm para o c-kit e para o PCNA, enquanto que o GDF-9 teve sua expressÃo reduzida em meio suplementado com jacalina. Em conclusÃo, jacalina e FSH foram capazes de promover a sobrevivÃncia e ativaÃÃo de folÃculos primordiais caprinos apÃs 6 dias de cultivo. A presenÃa de FSH aumentou a expressÃo do RNAm para PCNA e c-kit, enquanto que a presenÃa da jacalina reduziu a expressÃo do GDF-9.
The aims of this study were to investigate the effect of different concentrations of jacalin and the interaction of jacalin and FSH on survival, activation and gene expression of goat primordial follicles cultured in vitro. For this, fragments of ovarian cortex were cultured in Minimum Essential Medium (MEM) supplemented with different concentrations of jacalin (0, 10, 25, 50 and 100 mg/mL - experiment I) for one and six days. After the end of cultured period, the fragments of ovarian cortex were fixed for histology. Then, the percentage of primordial follicles in uncultured or cultured ovarian tissue in different treatments were evaluated. After determining the most effective concentration of jacalin (50 μg/mL), ovarian cortex fragments were cultured in MEM supplemented with jacalin (50 μg/ml), FSH (50 ng/ml) or both (experiment II). After 6 days of culture, the ovarian fragments were fixed for histology. Furthermore, for each treatment, tissue samples were collected to evaluate the expression profile of mRNA for c-kit, KL, GDF-9, BMP-15 and PCNA in goats ovarian follicles cultured in vitro for 6 days. The results showed that after six days of culture, the presence of 50 μg/ml jacalin in culture medium increased the percentage of normal follicles, and promoted a reduction in the percentage of primordial follicles and increase of developing follicles, when compared to control medium. In experiment II, jacalin or FSH stimulated primordial follicle activation and contributed to maintain follicle viability, but there was no positive interaction between these two substances. The levels of mRNA for BMP-15 and KL after in vitro culture of ovarian fragments in different treatments was not altered. However, the presence of FSH increased levels of mRNA for c-kit and PCNA, while the GDF-9 expression was reduced in medium supplemented with jacalin. In conclusion, jacalin and FSH were able to promote the survival and activation of goat primordial follicles after 6 days of culture. The presence of FSH increased expression mRNA of PCNA and c-kit, while the presence of jacalin reduced the expression of GDF-9.
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Passos, Jose Renato De Sousa. "ExpressÃo do sistema interleucina 1 (il-1) em folÃculos ovarianos bovinos e efeitos in vitro da il-1β na ativaÃÃo de folÃculos primordiais." Universidade Federal do CearÃ, 2015. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=14355.
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CoordenaÃÃo de AperfeÃoamento de Pessoal de NÃvel SuperiorO objetivo deste estudo foi investigar a expressÃo do sistema interleucina 1 (proteÃnas e RNAm de ligantes e receptores) e sua distribuiÃÃo nos ovÃrios de vacas cÃclicas, bem como avaliar os efeitos da IL-1β na sobrevivÃncia e ativaÃÃo de folÃculos primordiais in vitro. Os ovÃrios foram processados para a localizaÃÃo do sistema interleucina 1 em folÃculos prÃ-antrais e antrais utilizando as tÃcnicas de imunohistoquÃmica, qPCR e anÃlise de Western blot. Para os estudos in vitro, fragmentos ovarianos foram cultivados em α-MEM+ suplementado com IL-1β (0, 1, 10, 50 ou 100 ng/mL), e apÃs 6 dias foram processados para anÃlise histolÃgica. Os resultados de imunohistoquÃmica mostraram que a proteÃna para os integrantes do sistema interleucina I (IL-1β, IL-1RA, IL-1RI e IL-1RII) foram detectados em diferentes compartimentos foliculares. Infelizmente, o anticorpo testado para localizaÃÃo de IL-1α nÃo reagiu em ovÃrios bovinos. Todas as proteÃnas testadas foram observados no citoplasma dos oÃcitos e nas cÃlulas da granulosa de todas as categorias foliculares, e nas cÃlulas da teca de folÃculos antrais, com a exceÃÃo da IL-1α, que nÃo foi encontrada em nenhuma das cÃlula analisados. Foram observados nÃveis variÃveis de RNAm para o sistema interleucina 1 nas diferentes categorias foliculares analisadas. ApÃs 6 dias de cultivo, a presenÃa de IL-1β (10 ou 50 ng/mL) foi capaz de manter a percentagem de folÃculos normais e de promover a ativaÃÃo dos folÃculos primordiais. Em conclusÃo, os componentes do sistema de interleucina 1 sÃo expressos diferencialmente em cÃlulas ovarianas de acordo com a fase do desenvolvimento folicular. AlÃm disso, a IL-1β promove o desenvolvimento de folÃculos primordiais in vitro. Estes resultados sugerem um importante papel do sistema interleucina 1 na regulaÃÃo da foliculogÃnese em bovinos.
This study aims to investigate the expression of interleukin 1 system (proteins and mRNA of ligands and receptors) and its distribution in ovaries of cyclic cows, as well as to evaluate the effects of IL-1β on the survival and activation of primordial follicles in vitro. The ovaries were processed for localization of interleukin 1 system in preantral and antral follicles by immunohistochemical, qPCR and western blot analysis. For in vitro studies, ovarian fragments were cultured in α-MEM+ supplemented with IL-1β (0, 1, 10, 50 or 100 ng/mL), and aftes 6 days the tissues cultured were processed for histological analysis. Immunohistochemical results showed that the proteins for interleukin 1 system (IL-1β, IL-1RA, IL-1RI and IL-1RII) were detected in the various follicular compartments. Unfortunately, IL-1α antibodies tested did not react in bovine ovaries. All the proteins tested were observed in the cytoplasm of oocytes and granulosa cells from all follicular categories, and theca cells of antral follicles, with the exception that IL-1α has not been found in any analyzed cell. Variable levels of mRNA for the interleukin 1 system in the follicular size and classes analysed. After 6 days of culture, the presence of IL-1β (10 or 50 ng/mL) was effective in maintaining the percentage of normal follicles and in promoting primordial follicle activation. In conclusion, interleukin 1 system is differentially expressed in the ovarian cells according to the stage of follicular development. Moreover, IL-1β promotes the development of primordial follicles. These results suggest an important role of the interleukin 1 system in the regulation of folliculogenesis in bovine species.
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Grosbois, Johanne. "Regulation of human primordial follicle activation in vitro." Doctoral thesis, Universite Libre de Bruxelles, 2019. https://dipot.ulb.ac.be/dspace/bitstream/2013/282967/3/Grosbois.pdf.
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Producing competent and fertilizable oocytes from in vitro grown primordial follicles could revolutionize female infertility treatment, particularly using fertility preservation approaches that use cryopreserved ovarian tissue. However, the protracted length of folliculogenesis in humans makes follicular culture complex, and the mechanisms controlling the tightly-regulated activation of primordial follicles remain largely unknown. The delicate balance between follicular recruitment and quiescence might be affected by preservation procedures, such as ovarian fragmentation or in vitro culture, that disrupt crucial pathways, such as the Hippo and PI3K/Akt/mTOR signaling pathways, that are involved in this process. When activated, these pathways induce massive recruitment of primordial follicles and accelerate follicular growth in vitro, with potential negative consequences on future oocyte developmental competence. Therefore, we hypothesized that the inhibition of the PI3K/Akt/mTOR pathway might improve follicular growth by slowing down the activation process.In the first part of this thesis, we explored the potential benefit of inhibiting PI3K/Akt/mTOR signaling on the regulation of in vitro follicular activation and growth, as well as its impact on the Hippo pathway. The effect of everolimus (EVE), a specific mTORC1 inhibitor, was compared to the PI3K/Akt activators recently used to reinitiate the growth of residual follicles in the ovarian tissue of patients with premature ovarian insufficiency. We showed that short-term incubation of ovarian cortex with EVE partially delayed follicular recruitment while supporting follicle survival and steroidogenesis. However, morphological abnormalities were observed in all conditions, suggesting that EVE failed to protect follicles from accelerated in vitro growth-related defects.Our findings also provided evidence that ovarian fragmentation, which disrupts the Hippo pathway, contributes to the triggering of primordial follicle recruitment and early development of quiescent human follicles. Moreover, our data suggested that both PI3K/Akt and Hippo signaling could act synergistically to promote follicular activation and growth.In the second part of the project, we further investigated the integrity of EVE-treated follicles based on their ultrastructural and functional status. Our observations indicate that the integrity of oocyte and granulosa cells, as well as their physical contacts, were preserved in EVE and control conditions, although some in vitro grown follicles sustained cryopreservation- and culture- induced damage. We also found that short exposure to EVE allowed the maintenance of intra-follicular communication while preserving follicular developmental potential. Importantly, results obtained suggested that, at a similar developmental stage, cell coupling and oocyte growth may be improved in EVE-treated follicles.Altogether, these data provide better insight into the regulation of the follicular activation process and emphasize the importance of getting closer to physiological conditions to preserve follicle integrity. They also provide proof-of-concept evidence that reducing the initiation of growth is feasible, and suggest that mTORC1 inhibitors are a potentially useful pharmacological tool to regulate in vitro follicular growth.La production d'ovocytes compétents et fécondables à partir de follicules primordiaux développés in vitro pourrait révolutionner les traitements liés à l'infertilité féminine, en particulier les approches de préservation de la fertilité à partir du tissu ovarien cryopréservé. Cependant, la longue durée de la folliculogenèse chez l'Homme rend la culture folliculaire complexe, et les mécanismes contrôlant l'activation des follicules primordiaux restent largement inconnus. L’équilibre fragile entre quiescence folliculaire et entrée en croissance pourrait être affecté par la fragmentation ovarienne ou la culture in vitro elle-même, qui perturbent deux voies de signalisation cruciales: les voies Hippo et PI3K/Akt/mTOR, respectivement. Lorsqu'elles sont activées, elles induisent un recrutement massif de follicules primordiaux et accélèrent la croissance folliculaire in vitro, avec des conséquences potentiellement néfastes sur la capacité future des ovocytes à devenir compétents. Par conséquent, nous avons émis l’hypothèse que l’inhibition de la voie PI3K/Akt/mTOR pourrait améliorer la croissance folliculaire via un ralentissement du processus d’activation.Dans la première partie de cette thèse, nous avons exploré le potentiel bénéfice d’une inhibition de la voie PI3K/Akt/mTOR sur la régulation de l'activation et de la croissance folliculaire in vitro, ainsi que son impact sur la voie Hippo. L’effet de l’évérolimus (EVE), un inhibiteur spécifique de mTORC1, a été comparé à ceux d’activateurs de PI3K/Akt, récemment utilisés afin d’initier la croissance des follicules résiduels au sein de tissus ovarien de patientes en insuffisance ovarienne précoce. Nous avons montré que l'exposition à court terme de cortex ovarien à l'EVE retardait partiellement le recrutement folliculaire tout en préservant la survie et la stéroidogenèse des follicules. Toutefois, des anomalies morphologiques ont été observées dans toutes les conditions, ce qui suggère que l’EVE ne préserve pas les follicules de défauts liés à une croissance accélérée.Nos résultats ont également prouvé que la fragmentation ovarienne, en perturbant la voie Hippo, contribue au recrutement et au développement précoce des follicules primordiaux. De plus, les données obtenues suggèrent que les voies PI3K/Akt/mTOR et Hippo pourraient agir de manière synergique pour promouvoir l'activation et la croissance folliculaire.Dans la deuxième partie du projet, nous avons étudié la qualité des follicules traités avec de l’EVE en se basant sur des critères ultrastructural et fonctionnel. Nos observations ont indiqué que l'intégrité des ovocytes et des cellules de la granulosa ainsi que leurs contacts physiques était préservée dans les conditions EVE et contrôle, bien que certains follicules en croissance présentent des signes de dommages induits par la cryopréservation et la culture. Nous avons également constaté qu'une courte exposition à l’EVE permettait de maintenir les communications intra-folliculaires tout en préservant le potentiel de développement des follicules. De façon importante, les résultats obtenus suggèrent qu’à un stade de développement similaire, le couplage cellulaire et la croissance des ovocytes pourraient être améliorés dans les follicules traités à l’EVE.En conclusion, ces données contribuent à une meilleure compréhension de la régulation de l'activation folliculaire in vitro, et soulignent l'importance de mimer les conditions physiologiques pour préserver l'intégrité des follicules. Elles apportent également la preuve qu’un ralentissement de l’initiation de la croissance est réalisable, et suggèrent que l’utilisation d’inhibiteurs de mTORC1 pourrait représenter un outil pharmacologique efficace pour réguler la croissance folliculaire in vitro.
Doctorat en Sciences biomédicales et pharmaceutiques (Médecine)
info:eu-repo/semantics/nonPublished
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Spence, Susan Claire. "Exploring the role of the phosphatidylinositol-3'-kinase (PI3K) pathway in primordial follicle activation and subsequent development." Thesis, University of Edinburgh, 2016. http://hdl.handle.net/1842/23659.
Full textAbstract:
Mammalian females form their germ cells (oocytes) before or shortly after birth. The oocytes interact with somatic cells to form primordial follicles, creating the quiescent population from which oocytes will be recruited to grow throughout life. A female’s fertility life span is therefore, dependant on the size of this pool and the rate at which primordial follicle are activated to grow. However, there is still much we do not know about the quiescent follicle population and the mechanisms that control their recruitment into the growing follicle population are still unclear. There is evidence that the phosphoinositide-3-kinase (PI3K) pathway is key to activation of follicle growth. The role of the PI3K pathway has been primarily explored in the rodent model and has highlighted this pathway’s importance both in the activation of quiescent follicle growth and maintaining dormancy of the quiescent follicle population. This thesis aimed to explore if the PI3K pathway played a similar role in a large mono-ovulatory species as it does in the small polyovulatory rodent species. Bovine is a mono-ovulate species, which has similar attributes in its reproduction and folliculogenesis to the human in vivo; therefore using an in vitro bovine model might be a valuable indication of the role of the PI3K pathway in the human. Initial experiments tested if the bovine was a good model for human primordial follicle activation in an in vitro environment. It was observed that the bovine and human had comparative levels of activation and subsequent increases in both the primary and secondary follicle populations within an in vitro culture system. These similarities indicate that the bovine is a relevant model for the human in vitro. It is not possible to culture the entire bovine ovary. Therefore knowing the location of the primordial follicles is important to establishing what region(s) of the ovary to use. The overall concentration of ovarian follicles was higher in the cortex and gradually declined through the consecutive inner layers of the ovary. The distribution of the ovarian follicle populations were different in each distinctive region of the ovary with the quiescent follicles representing a much larger proportion of the ovarian follicle population in the cortex compared to the inner regions of the ovary. The location an ovarian follicle in the ovary was seen to influence its health in both the quiescent and growing follicle populations, with reduced health seen in the IV inner layers of the ovary compared to the cortex. This resulted in very few healthy quiescent follicles outside of the cortex region making it the more favourable region to culture in functional studies. The role of the PI3K pathway was therefore explored using an in vitro bovine model using the pharmacological compounds bpV (HOpic) and 740Y-P, both of which caused an up-regulation of the PI3K-pathway. It was observed that up-regulation of the PI3K pathway caused an increase in the activation of the quiescent follicle population, and the resulting primary follicles were larger in size. However, there was reduced health in both the growing and quiescent follicle populations. The ill health appears to be due to a disruption in the co-ordination of growth between oocyte and granulosa cells in the ovarian follicles, leading to enlarged oocytes in both the primary follicles and quiescent follicles. Although the PI3K pathway caused an increase in quiescent follicle activation and larger primary follicles there was no increase in the number of viable large secondary follicles obtained. The growth of the secondary follicles was unaltered by the initial activation of the quiescent follicles via the PI3K pathway. These experiments show that the PI3K pathway plays a role in primordial follicle activation in large mono-ovulate species. However, up-regulating the PI3K pathway results in a decrease in health of the quiescent and primary follicle populations, thus limiting its immediate value as a therapeutic target. This study has improved our understanding of the role of the PI3K pathway in primordial follicle activation in a large mono-ovulate species. It has highlighted that the up-regulation of the PI3K pathway using both bpV (HOpic) and 740Y-P increases the activation of the bovine ovarian follicles in vitro. However, up-regulating the PI3K pathway disrupts the development of the ovarian follicles resulting in retarded growth and thereby a decrease in the survival of both the quiescent and growing follicle populations. The similarities in activation, growth and development between the bovine and the human in vitro indicate that the results observed in the bovine are a good indication of what would occur in the human. This study has also improved our understanding of the location, distribution and viability of the ovarian follicle population within the ovary.
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Adhikari, Deepak. "Signaling pathways in the development of female germ cells." Doctoral thesis, Umeå universitet, Institutionen för medicinsk kemi och biofysik, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-88309.
Full textAbstract:
Primordial follicles are the first small follicles to appear in the mammalian ovary. Women are born with a fixed number of primordial follicles in the ovaries. Once formed, the pool of primordial follicles serves as a source of developing follicles and oocytes. The first aim of this thesis was to investigate the functional role of the intra-oocyte signaling pathways, especially the phosphatidylinositol-3 kinase (PI3K) and mammalian target of rapamycin complex 1 (mTORC1) pathways in the regulation of primordial follicle activation and survival. We found that a primordial follicle remains dormant when the PI3K and mTORC1 signaling in its oocyte is activated to an appropriate level, which is just sufficient to maintain its survival, but not sufficient for its growth initiation. Hyperactivation of either of these signaling pathways causes global activation of the entire pool of primordial follicles leading to the exhaustion of all the follicles in young adulthood in mice. Mammalian oocytes, while growing within the follicles, remain arrested at prophase I of meiosis. Oocytes within the fully-grown antral follicles resume meiosis upon a preovulatory surge of leutinizing hormone (LH), which indicates that LH mediates the resumption of meiosis. The prophase I arrest in the follicle-enclosed oocyte is the result of low maturation promoting factor (MPF) activity, and resumption of meiosis upon the arrival of hormonal signals is mediated by activation of MPF. MPF is a complex of cyclin dependent kinase 1 (Cdk1) and cyclin B1, which is essential and sufficient for entry into mitosis. Although much of the mitotic cell cycle machinery is shared during meiosis, lack of Cdk2 in mice leads to a postnatal loss of all oocytes, indicating that Cdk2 is important for oocyte survival, and probably oocyte meiosis also. There have been conflicting results earlier about the role of Cdk2 in metaphase II arrest of Xenopus oocytes. Thus the second aim of the thesis was to identify the specific Cdk that is essential for mouse oocyte meiotic maturation. We generated mouse models with oocytespecific deletion of Cdk1 or Cdk2 and studied the specific requirements of Cdk1 and Cdk2 during resumption of oocyte meiosis. We found that only Cdk1 is essential and sufficient for the oocyte meiotic maturation. Cdk1 does not only phosphorylate the meiotic phosphoproteins during meiosis resumption but also phosphorylates and suppresses the downstream protein phosphatase 1, which is essential for protecting the Cdk1 substrates from dephosphorylation.
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Chen, Ying. "The role of steroids in the regulation of oocyte cyst breakdown and primordial follicle assembly in the neonatal mouse ovary." Related electronic resource: Current Research at SU : database of SU dissertations, recent titles available, full text:, 2008. http://wwwlib.umi.com/cr/syr/main.
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Jagarlamudi, Krishna Rao. "The functional roles of the intra-oocyte phosphatidylinositol 3-kinase (PI3K) signaling in controlling follicular development in mice." Doctoral thesis, Umeå : Umeå university, 2009. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-26110.
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Lopes, TÃnia de Azevedo. "InfluÃncia da Artrite Encefalite Caprina sobre a expressÃo de RNAm para GDF-9, BMP-15 e BMPR-IB em folÃculos ovarianos e ativaÃÃo in vitro de folÃculos primordiais em meio suplementado com fitohemaglutinina e EGF." Universidade Federal do CearÃ, 2014. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=12890.
Full textAbstract:
Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgicoO objetivo deste trabalho foi investigar os efeitos da artrite encefalite caprina (CAE) sobre a expressÃo de BMP-15, BMPR-IB e GDF-9 em folÃculos ovarianos, bem como os efeitos de fitohemaglutinina (PHA) e EGF na sobrevivÃncia e ativaÃÃo de folÃculos primordiais, e na expressÃo de genes para o sistema de TNF-α no tecido ovariano cultivado caprino. Os nÃveis de BMP-15, BMPR-IB e GDF-9 em folÃculos primordiais/primÃrios e secundÃrios, bem como em CCOs e parede folicular de folÃculos antrais foram avaliados por PCR em tempo real (experimento 1). Para os estudos in vitro, fragmentos de tecido ovariano foram cultivados por seis dias em α-MEM sozinho ou suplementado com EGF (100ug), PHA (10μg/mL) ou ambos (experimento 2). Antes e depois do cultivo, o tecido ovariano foi processado para anÃlise morfolÃgica ou armazenado para avaliar a expressÃo de RNAm para TNF-α e seus receptores. Os resultados mostraram que a expressÃo de BMP-15 e GDF-9 em folÃculos primordiais/primÃrios de cabras infectadas foram significativamente maiores do que em animais saudÃveis, mas a expressÃo de GDF-9 em folÃculos secundÃrios de cabras infectadas foi significativamente menor. AlÃm disso, a expressÃo de RNAm para BMP-15 na parede folicular de folÃculos antrais de cabras infectadas foi significativamente maior do que em cabras saudÃveis. ApÃs o cultivo dos fragmentos ovarianos em todos os meios testados, observou-se a reduÃÃo nos percentuais de folÃculos primordiais, e aumento de folÃculos em desenvolvimento quando comparado ao grupo controle nÃo cultivado. AlÃm disso, houve um aumento significativo no diÃmetro folicular apÃs cultivo em meio suplementado com EGF. ApÃs o cultivo de tecido ovariano de cabras infectadas em meio suplementado com PHA, os folÃculos primordiais apresentavam diÃmetros maiores do que os de animais saudÃveis. AlÃm disso, observou-se um aumento nos nÃveis de RNAm para TNF-α apÃs cultivo de tecido ovariano na presenÃa de ambos EGF e PHA em animais saudÃveis, mas este mesmo tratamento proporcionou uma reduÃÃo de RNAm para TNF-α e aumento dos transcritos de TNFR-II em animais infectados. Pode-se concluir que a CAE influencia a expressÃo de RNAm para BMP-15 e GDF-9 em folÃculos ovarianos caprinos e a PHA e o EGF diferencialmente regulam a expressÃo de TNF-α e TNFR-II em tecidos ovarianos.
This study aims to investigate the effects of caprine arthritis encephalitis (CAE) on the expression of BMP-15, BMPR-IB and GDF-9 in ovarian follicles, as well as the effects of phytohemagglutinin (PHA) and EGF on the survival and activation of primordial follicles, and on expression of mRNA for TNF-α and its receptors in cultured goat ovarian tissue. The levels of BMP-15, BMPR-IB and GDF-9 in primordial/primary and secondary follicles, as well as in COCs and follicular walls from antral follicles were evacuated by real-time PCR (experiment 1). Ovarian tissues were cultured for six days in α-MEM+ alone or supplemented with EGF (100Âg/mL), PHA (10Âg/mL) or both (experiment 2). Before and after culture, ovarian fragments were processed for morphological analysis or stored to evaluate the expression of mRNA for TNFα and its receptors. The results showed that the expression of BMP-15 and GDF-9 in primordial/primary follicles from infected goats was significantly higher than in health animals, but the expression of GDF-9 in secondary follicles from infected goats was significantly lower. Additionally, the expression of mRNA for BMP-15 in follicular wall of antral follicles from infected goats was significantly higher than in healthy goats. After culturing ovarian fragments in all tested media, reduced percentages of primordial follicles, and increased of developing follicles was observed when compared to uncultured control. Furthermore, there was a significant increase in follicular diameter after culture in medium supplemented with EGF. Ovarian tissue from infected goats cultured in medium supplemented with PHA had primordial follicles with higher diameters than those from healthy animals. An increase in the levels of mRNAs for TNF-α was observed after culturing ovarian tissue in presence of both EGF and PHA in healthy animals, but this same treatment promoted a reduction of mRNAs for TNF-α and and increase of TNFR-II transcripts in infected animals. In conclusion, CAE influences the expression of mRNA for BMP-15 and GDF-9 in goat ovarian follicles and PHA and EGF differentially regulate the expression of TNFα and TNFR-II in cultured ovarian tissue.
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Torre, Antoine. "Les alternatives à la greffe de fragments de cortex ovarien dans la conservation de la fertilité chez la fille devant subir un traitement gonadotoxique : contribution à l'étude de la xénogreffe de follicules primordiaux et de la cryoconservation d'ovaire entier avec son pédicule vasculaire." Thesis, Lyon 1, 2012. http://www.theses.fr/2012LYO10150/document.
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Les traitements anticancéreux utilisés sur la femme jeune conduisent de plus en plus à laguérison, au prix d’une altération de la fertilité par atteinte significative de la réserveovarienne. Ces patientes à risque d’atrésie folliculaire accélérée peuvent bénéficier d’une sauvegarde de leur fertilité, le plus souvent par techniques conventionnelles d’assistance médicale à la procréation, permettant la conservation d’ovocytes et/ou d’embryons. Cependant, ces techniques ne sont pas adaptées aux patientes pré-pubères ou à celles porteuses de pathologies imposant un traitement immédiat ou contrindiquant unestimulation hormonale. Chez ces patientes, la cryoconservation du tissu ovarien est indiquée. A ce jour, au moins 18 enfants sont nés après greffes avasculaires de fragments ovariens cryoconservés, mais ces greffes ont une durée de vie limitée par souffrance ischémique initiale et comportent un risque de réimplantation de cellules malignes. La transplantation micro-vasculaire d’ovaire entier a été proposée pour palier la souffrance ischémique, tandis que l’isolation des follicules primordiaux éviterait la récidive néoplasique induite par la greffe .Dans ce travail scientifique, nous nous sommes d'abord intéressés à l'isolation des follicules primordiaux humains. Par un modèle de xénogreffe, nous avons établi que ces follicules isolés et greffés dans un caillot de fibrine pouvaient poursuivre leur développement jusqu'austade antral. Ces travaux ont été précurseurs aux progrès récents sur la culture in vitro defollicules primordiaux encapsulés. Dans la suite du travail, nous avons contribué à l'étude de la vitrification d'ovaire entier de brebis avec son pédicule vasculaire. Nous avons ainsi établi l'altération de la viabilité dupédicule vasculaire de ces organes entiers vitrifiés, alors que des études thermodynamiques préalables prouvaient que ces pédicules vasculaires étaient bien vitrifiés. Des phénomènes de cristallisation étant survenus au réchauffement de ces organes, avec pour point de départ la zone péri-ovarienne, nous nous sommes intéressés à l'exposition deces ovaires lorsqu'ils sont perfusés par les cryoprotecteurs. Nous avons montré que la perfusion d'ovaires s'accompagne de zones non exposées dans plus de 50% des ovaires perfusés, d'autant plus que l'expérimentateur est novice, que la surface de la tranche ovarienne est petite et qu'il existe un corps jaune visible. Ces zones incomplètement exposées seraient donc responsables de cristallisation lors de la vitrification de l'organe, catalysant une prise en glace globale de l'organe lors du réchauffement. Le problème serait donc plus dans une exposition incomplète aux cryoprotecteurs que dans la nature même de ces cryoprotecteurs. L'équipe lyonnaise avait déjà rapporté l'absence d'efficacité du protocole de vitrification utilisant le cryoprotecteur « VS4 » dans le rétablissement de la fertilité de brebis. Nous avons confirmé que l'utilisation du cryoprotecteur « VM3 » (vitrifiant de manière plus performanteque « VS4 »), ne permettait pas non plus le rétablissement de la fertilité après autotransplantation d'ovaires vitrifiés à la brebis. En revanche, nous avons obtenu une gestation après auto-transplantation d'ovaire de brebis cryoconservé par congélation lente, ce qui est le deuxième cas rapporté au monde. Nos résultats suggèrent que cette vitrification incomplète due à une mauvaise exposition des ovaires est l'un des principaux obstacles à la conservation de la fertilité par vitrification d'ovaire entier avec son pédicule vasculaireAnticancer treatments used in young women more and more lead to recovery, but with fertility disturbance due to ovarian reserve insults. These women at risk of accelerated follicle atresia can safe guard there fertility. Most of the time, it is performed with conventional Assisted Reproductive Techniques, allowing ovocytes or embryos banking. However these treatments are available neither for girls before puberty, nor when thedisease requires emergency treatments, nor for hormone dependant disease. In these cases, ovarian tissue cryobanking is indicated. To date, at least 18 babies have been born after cryopreservation and replacement of ovarian cortical strips but these grafts have a short lifespan due to initial ischemic damages and can reintroduce cancer cells on a cured woman. To control ischemic damage, cryopreservation of whole ovaries with their vascular pedicle has been proposed where as isolation of early follicles could manage the cancer reintroduction risk. In this scientific work, we first focused on isolation of early follicles. Using a xenograft model to mice with plasma clot as a vehicle, we showed that human isolated follicles can pursuit their development up to antral stage. This work motivates further progress in in-vitro cultureof encapsulates early follicles. In the second part of this work, we contributed to knowledge on vitrification of whole eweovaries with their vascular pedicle. We thus established impaired vascular viability of whole“VS4” vitrified ovaries, whereas previous calorimetric studies founded these vascular pedicles to be completely vitrified. As warming phase crystallization happened, starting from the area surrounding the ovary, we focused on the ovarian exposition when it is perused with cryoprotectors. We showed that unexposed parts are present in more than 50% of perfused ovaries, as much as the slide surface is small, a corpus luteum is present and the experimenter is inexperienced. These unexposed zones could be responsible for focal freezing during vitrification, these frozen focicatalyzing the whole organ ice crystallization during the warming phase. Hence, whole ovary vitrification failure could be due to improper cryoprotectors exposition of the organ ratherthan the inability of these cryoprotectors to promote proper tissue vitrification.Our team already failed to preserve fertility with “VS4” vitrified ewe ovaries. Neither were we able to preserve fertility with “VM3” vitrified ewe ovaries (this last cryoprotector being amore potent vitrificant solution than “VS4”), suggesting that vitrification is an inappropriate way to cryopreserve whole ewe ovaries for fertility purpose. On the other hand, we obtained a gestation after transplantation of slow frozen ewe ovaries. This gestation is the second reported worldwide. Our results suggest that vitrification of whole ovaries is impaired by improper cryoprotector exposition of ovaries through perfusion route
Books on the topic "Primordial follicles"
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A. Bulbul, Tuba Bulbul, V. Ozdemir, M.S. Akosman, Elmas Ulutas, and O. Yilmaz. Biphasic effect of nitric oxide on development of ovarian primordial and primary follicles in laying quail. Verlag Eugen Ulmer, 2015. http://dx.doi.org/10.1399/eps.2015.105.
Full textBook chapters on the topic "Primordial follicles"
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Guraya, Sardul S. "Primordial Follicle." In Biology of Ovarian Follicles in Mammals. Springer Berlin Heidelberg, 1985. http://dx.doi.org/10.1007/978-3-642-70154-2_2.
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Fortune, J. E. "Activation of Primordial Follicles." In The Future of the Oocyte. Springer Berlin Heidelberg, 2002. http://dx.doi.org/10.1007/978-3-662-04960-0_2.
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Myers, Michelle, and Karla J. Hutt. "Damage Control in the Female Germline: Protecting Primordial Follicles." In Oogenesis. Springer London, 2012. http://dx.doi.org/10.1007/978-0-85729-826-3_3.
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Telfer, Evelyn E. "Culture of Human Ovarian Follicles from Primordial Stages to Maturity." In Female and Male Fertility Preservation. Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-030-47767-7_30.
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Adhikari, Deepak, and Kui Liu. "Regulation of Quiescence and Activation of Oocyte Growth in Primordial Follicles." In Oogenesis. Springer London, 2012. http://dx.doi.org/10.1007/978-0-85729-826-3_4.
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Nappi, Luigi, Felice Sorrentino, Francesca Greco, Laura Vona, Francesco Maria Zullo, and Stefano Bettocchi. "Pathophysiology of Female Reproduction and Clinical Management." In Practical Clinical Andrology. Springer International Publishing, 2022. http://dx.doi.org/10.1007/978-3-031-11701-5_16.
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AbstractThe female genital system is made up of dynamic organs that change during the woman’s life cycle. Ovarian cycle consists of the growth and development of the ovarian follicle, its bursting, and transformation into the corpus luteum with relative production of estrogens and progesterone.The normal menstrual cycle is the result of the integration of the primary neuroendocrine complex (the hypothalamus–pituitary–ovarian axis) into a control system regulated by a series of peripheral mechanisms of feedback and nerve signals that result in the release of a single mature oocyte from a pool of hundreds of thousands of primordial oocytes. Alterations of these mechanisms can lead to pathological conditions and affect fertility of patients.
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Mulheron, G. W., S. L. Quattropani, and J. M. Nolin. "On the Intrinsic Ovarian Control of the Developmental Transition from Primordial to Primary Follicle." In Advances in Experimental Medicine and Biology. Springer US, 1987. http://dx.doi.org/10.1007/978-1-4684-5395-9_52.
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Amorim, Christiani A., and Carolina M. Lucci. "Survival of Primordial Follicles." In Fertility Preservation, 2nd ed. Cambridge University Press, 2021. http://dx.doi.org/10.1017/9781108784368.033.
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Piltonen, Terhi, and Juha Tapanainen. "Ovarian and Uterine Development from Fetal Life to Puberty." In Oxford Textbook of Endocrinology and Diabetes 3e, edited by John A. H. Wass, Wiebke Arlt, and Robert K. Semple. Oxford University Press, 2021. http://dx.doi.org/10.1093/med/9780198870197.003.0151.
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Human fetal organogenesis is a complex process starting 4 weeks post conception. The gender specific gonads can be distinguished as early as by the GW 8 and the process is driven by the sex determining region on the Y-chromosome (SRY) among other genes that drive fetal testosterone and AMH effects. In the absence of anti-Müllerian hormone (AMH) the Müllerian ducts will develop to uterus and fallopian tubes, and without androgen influence the urogenital sinus will form as female external genitalia. Ovarian primordial follicles reach the highest number of 7 million around mid-gestation after which the number starts to decrease by means of apoptosis and only 2 million primordial follicles are left at the time of birth and less than half of million at puberty. The pituitary–ovarian axis of the fetus is activated at mid-gestation, after which levels of gonadotropins decrease towards the term, and become activated again after birth resulting in minipuberty. The quiescent period in gonadotrophins and sex steroid production remains during childhood ends before puberty as a consequence of maturation of the hypothalamus–pituitary–ovarian axis. During reproductive life around 400 follicles will ovulate with concomitant decrease of follicle pool through apoptosis. The follicle reserve is exhausted around the age of 50 years resulting into menopause.
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"Maturation of primordial follicles – the next step." In In Vitro Maturation of Human Oocytes. CRC Press, 2006. http://dx.doi.org/10.1201/b14636-21.
Full textConference papers on the topic "Primordial follicles"
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Hosoda, Masaki, Daisuke Oida, Koichiro Ito, Seido Takae, Nao Suzuki, and Kosuke Tsukada. "Ex vivo sensing of primordial follicles in ovarian tissues by spectral-domain optical coherence tomography." In Biomedical Applications in Molecular, Structural, and Functional Imaging, edited by Barjor S. Gimi and Andrzej Krol. SPIE, 2022. http://dx.doi.org/10.1117/12.2607462.
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Liebenthron, J., J. Reinsberg, R. Fimmers, et al. "Serum AMH concentration has limited prognostic value for the density of primordial follicles questioning AMH as a parameter for the real ovarian reserve." In 62. Kongress der Deutschen Gesellschaft für Gynäkologie und Geburtshilfe – DGGG'18. Georg Thieme Verlag KG, 2018. http://dx.doi.org/10.1055/s-0038-1671640.
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