Literatura académica sobre el tema "Vinclozolin"

Vinclozolin is one of the most used fungicides in the control of fungi in fruits, vegetables, and ornamental plants. The effects of its exposure on different organs have been described, but information regarding its relevance to vinclozolin-induced nephrotoxicity is largely missing. This study focuses on the potential mechanism of vinclozolin-induced nephrotoxicity. CD1 male mice were administered vinclozolin (100 mg/kg) by oral gavage for 28 days. Vinclozolin administration decreased body weight over the treatment period and at the end of the experiment, increased the ratio of kidney weight to body weight and increased serum urea nitrogen and creatinine contents. Vinclozolin also induced histopathological alterations, including tubular dilatation and necrosis and impaired the integrity of the renal-tubular architecture and kidney fibrosis. The analyses conducted showed that vinclozolin administration altered the mRNA levels of mitochondrial function-related proteins (SIRT3, SIRT1, PGC-1α, TFAM, NRF1, VDAC-1, and Cyt c) and oxidative stress (increased lipid peroxidation and decreased total antioxidative capacity, catalase, and superoxide dismutase activities, glutathione levels, and glutathione peroxidase activity) in the kidneys. Furthermore, vinclozolin induced toxicity that altered Nrf2 signalling and the related proteins (HO-1 and NQO-1). Vinclozolin administration also affected both the extrinsic and intrinsic apoptotic pathways, upregulating the expression of proapoptotic factors (Bax, Caspase 3, and FasL) and downregulating antiapoptotic factor (Bcl-2) levels. This study suggests that vinclozolin induced nephrotoxicity by disrupting the transcription of mitochondrial function-related factors, the Nrf2 signalling pathway, and the extrinsic and intrinsic apoptotic pathways.

Treatment of actively growing Botrytis cinerea hyphae with micromolar concentrations of the dicarboximide fungicide vinclozolin resulted in significant alterations in the growth rate, morphology, and chemical composition of the cells. The addition of vinclozolin resulted in an immediate and severe reduction in the hyphal growth rate and a retardation in the emergence of the second germ tube. Cells treated with vinclozolin had a lower content of pool metabolites than control cells, and this difference increased with time of exposure to the fungicide. In contrast, vinclozolin-treated cells had a higher chitin concentration than control cells. These biochemical alterations were followed by the disorganization and clearing of cells, and by the appearance of dense and dark masses outside the hyphae, presumably composed of cell debris. Hyphae exposed to vinclozolin were more curved and branched and had shorter cells than the controls. The results indicate that vinclozolin causes a slow but generalized leakage of pool metabolites; this release precedes cell lysis and is not the result of a rapid and gross damage to the cytoplasmic membrane.Key words: vinclozolin, Botrytis cinerea, pool metabolites, membrane damage.

Vinclozolin is an endocrine-disrupting chemical (EDC) that binds with high affinity to the androgen receptor (AR) and blocks the action of gonadal hormones on male reproductive organs. An alternative mechanism of action of Vinclozolin involves transgenerational effects on the male reproductive tract. We previously reported in utero Vinclozolin exposure-induced prostatitis (prostate inflammation) in postpubertal rats concurrent with down-regulation of AR and increased nuclear factor-κB activation. We postulated the male reproductive abnormalities induced by in utero Vinclozolin exposure could be reversed by testosterone supplementation, in contrast to the permanent modifications involving DNA methyltransferases (Dnmts) described by others. To test this hypothesis, we administered high-dose testosterone at puberty to Vinclozolin-treated rats and determined the effect on anogenital distance (AGD); testicular germ cell apoptosis, concentration of elongated spermatids, and the onset of prostatitis. Concurrently we examined Dnmt1, −3A, −3B, and −3L mRNA expression. Consistent with previous reports, in utero exposure to Vinclozolin significantly reduced AGD, increased testicular germ cell apoptosis 3-fold, reduced elongated spermatid number by 40%, and induced postpubertal prostatitis in 100% of exposed males. Administration of high-dose testosterone (25 mg/kg) at puberty normalized AGD, reduced germ cell apoptosis, and restored elongated spermatid number. Testosterone restored AR and nuclear factor-κB expression in the prostate and abolished Vinclozolin-induced prostatitis. Altered Dnmt expression was evident with in utero Vinclozolin exposure and was not normalized after testosterone treatment. These data demonstrate in utero Vinclozolin-induced male reproductive tract abnormalities are AR mediated and reversible and involve a mechanism independent of Dnmt expression.

Endocrine-disrupting substances (EDS) are common and pervasive in our environment and pose a serious risk to both human and animal health. Endocrine-disrupting compounds (EDCs) have been associated with a variety of detrimental human health effects, including respiratory issues, as a result of their ability to disrupt cell physiology. Vinclozolin ((RS)-3-(3,5-Dichlorophenyl)-5-methyl-5-vinyloxazolidine-2,4-dione) is a common dicarboximide fungicide used to treat plant diseases. Several studies have analyzed the effects of vinclozolin exposure on the reproductive system, but less is known about its effect on other organs such as the lung. Mice were exposed for 28 days to orally administered vinclozolin at a dose of 100 mg/kg. Vinclozolin exposure induced histological alterations and collagen depositions in the lung. Additionally, vinclozolin induced inflammation and oxidative stress that led to lung apoptosis. Our study demonstrates for the first time that the toxicological effects of vinclozolin are not limited to the reproductive system but also involve other organs such as the lung.

We studied sequelae of prenatal plus infantile exposure of male rabbits to vinclozolin, because it is ingested by women and children. Female Dutch-Belted rabbits (7–10/group) were treated daily per orum from gestation day 15 through post-natal week 4 to provide 0, 7.2, or 72 mg vinclozolin/kg dam’s body weight/day. Vinclozolin had no effect on maintenance of pregnancy, growth of pups, age at testicular descent or weight of organs. Concentrations of serum LH or testosterone at 6, 12, or 24 weeks of age were unaffected. However, FSH was lower (P< 0.05) in both vinclozolin groups at all three ages. Following injection of GnRH at 12 or 24 weeks, the increase in FSH was less (P< 0.05) in both vinclozolin groups, as was testosterone at 12 weeks of age. After full sexual maturity, 2 of 7 low dose rabbits were uninterested in female or male teasers and never achieved erection or ejaculation. Overall, rates of ejaculation failure were: control 0% (0/48), low dose 29% (12/42), and high dose 5% (3/60). Daily sperm production per gram of testis and total number of sperm per ejaculate in both vinclozolin groups were similar (P> 0.1) to controls. However, semen from vinclozolin rabbits contained over two times more (P< 0.05) morphologically abnormal spermatozoa, mostly nuclear and acrosomal defects, than semen from controls. Seminiferous tubules with degenerative changes were more frequent (P< 0.05) in vinclozolin rabbits than in controls. Lesions included syncytia of spherical spermatids and desquamation of germ cells. Hence, developmental exposure to vinclozolin caused presumably permanent changes in copulatory ability, secretion of FSH, and spermiogenesis.

Exposure to environmental endocrine disruptors may interfere with nervous system’s activity. Fungicides such as tebuconazole, triadimefon, and vinclozolin have antifungal activities and are used to prevent fungal infections in agricultural plants. In the present study, we studied effects of tebuconazole, triadimefon, and vinclozolin on rat’s neurosteroidogenic 5α-reductase 1 (5α-Red1), 3α-hydroxysteroid dehydrogenase (3α-HSD), and retinol dehydrogenase 2 (RDH2). Rat’s 5α-Red1, 3α-HSD, and RDH2 were cloned and expressed in COS-1 cells, and effects of these fungicides on them were measured. Tebuconazole and triadimefon competitively inhibited 5α-Red1, with IC50 values of 8.670 ± 0.771 × 10−6 M and 17.390 ± 0.079 × 10−6 M, respectively, while vinclozolin did not inhibit the enzyme at 100 × 10−6 M. Triadimefon competitively inhibited 3α-HSD, with IC50 value of 26.493 ± 0.076 × 10−6 M. Tebuconazole and vinclozolin weakly inhibited 3α-HSD, with IC50 values about 100 × 10−6 M, while vinclozolin did not inhibit the enzyme even at 100 × 10−6 M. Tebuconazole and triadimefon weakly inhibited RDH2 with IC50 values over 100 × 10−6 M and vinclozolin did not inhibit this enzyme at 100 × 10−6 M. Docking study showed that tebuconazole, triadimefon, and vinclozolin bound to the steroid-binding pocket of 3α-HSD. In conclusion, triadimefon potently inhibited rat’s neurosteroidogenic enzymes, 5α-Red1 and 3α-HSD.

Endocrine disruptor exposure during gonadal sex determination was previously found to induce male rat adult onset transgenerational disease (F1–F4 generation), and this was associated with an alteration in the epigenetic (i.e., DNA methylation) programming of the male germ line. The current study was designed to characterize the transgenerational disease phenotypes of the female adult offspring. Pregnant rats (F0 generation) were treated transiently with vinclozolin (i.e., fungicide with anti-androgenic activity) on embryonic (E) days E8–E14 of gestation. F1 control and vinclozolin generation offspring from different litters were mated to produce F2 offspring, and similarly F2 generation animals produced F3 generation offspring. Observations demonstrated that 9 out of 105 pregnant rats (8.6%) from the vinclozolin F1–F3 generations exhibited uterine hemorrhage and/or anemia late in pregnancy. None (0 out of 82) of the control F1–F3 generation females had similar pregnancy problems. Complete blood cell counts and serum chemistry profiles demonstrated that selected vinclozolin generation animals, but not controls, exhibited marked regenerative anemia in late pregnancy. Examination of kidney histology revealed moderate or severe glomerular abnormalities in 67% of the vinclozolin F2 and F3 generation adult females compared with 18% of the controls. Adult female vinclozolin generation animals also developed various types of tumors in 6.5% of the animals (11 out of 170), while 2% of control-line animals (3 out of 151) developed mammary tumors. Observations demonstrate that vinclozolin exposure during gonadal sex determination promotes a transgenerational increase in pregnancy abnormalities and female adult onset disease states.

Sclerotinia drop is a major disease of lettuce caused by two soilborne fungi, Sclerotinia minor and S. sclerotiorum. Fungicides such as dicloran (Botran), iprodione (Rovral), and vinclozolin (Ronilan) are currently available in the United States to manage this disease. Studies were conducted to investigate the relative effect of some new fungicides, including boscalid, fenhexamid, fluazinam, and fludioxonil, in comparison with vinclozolin, on growth of S. minor and S. sclerotiorum in agar plate tests as well as control of lettuce drop in the field. At a rate of 0.001 μg/ml, all tested compounds only suppressed mycelial growth of either pathogen from 0 to 20%. At 0.01 μg/ml, mycelial growth of S. minor was reduced 82 to 84% by fludioxonil and fluazinam and only 1 to 16% by boscalid, fenhexamid, and vinclozolin. At the same rate, mycelial growth of S. sclerotiorum was reduced 78% by fluazinam and from 0 to 12% by boscalid, fludioxonil, fenhexamid, and vinclozolin. At 0.1 μg/ml, all tested chemistries except vinclozolin inhibited mycelial growth of S. minor from 70 to 98%, whereas growth of S. sclerotiorum was suppressed 95 to 99% by fludioxonil and fluazinam, significantly less (40 to 47%) by boscalid and fenhexamid, and not at all by vinclozolin. At a rate of 1.0 μg/ml, all tested fungicides reduced mycelial growth of S. minor and S. sclerotiorum from 87 to 100% and 77 to 100%, respectively. Mycelial growth emerging from sclerotia of S. minor was reduced from 98 to 100% by all fungicides tested at a rate of 1.0 μg/ml, whereas growth from sclerotia of S. sclerotiorum was suppressed from 90 to 96% by fenhexamid, fludioxonil, fluazinam, and vinclozolin. In lettuce plots infested with S. minor, boscalid and fluazinam provided the highest level of disease control, significantly greater than that achieved with fenhexamid, fludioxonil, and vinclozolin. In the presence of S. sclerotiorum, the highest degree of disease suppression occurred with application of fluazinam, fludioxonil, and vinclozolin, whereas the least effective compound was fenhexamid. Boscalid and fluazinam were more effective against lettuce drop caused by S. minor than disease caused by S. sclerotiorum.

In 1996 and 1997, 325 isolates of Botrytis cinerea were collected from 35 commercial greenhouses growing ornamental crops in South Carolina to determine the incidence of resistance to benzimidazole and dicarboximide fungicides. Conidium germination was assessed on a defined agar medium amended with either thiophanate-methyl (a benzimidazole) or vinclozolin (a di-carboximide). A total of 53 representative isolates were evaluated further for conidium germination and mycelium growth on fungicide-amended medium and for infection of geranium seedlings treated with thiophanate-methyl or vinclozolin at label rates. Isolates were considered sensitive to thiophanate-methyl or vinclozolin when the effective concentration of the fungicide active ingredient resulting in 50% inhibition of germination (EC50-germ) was ≤5 μg/ml or when the effective concentration of fungicide active ingredient resulting in 50% inhibition of mycelium growth (EC50-growth) was ≤1 μg/ml. Of all isolates, 81% (262/325) were resistant to thiophanate-methyl and 69% (223/325) were resistant to vinclozolin. Four phenotypes were observed: sensitive to both fungicides (17%), resistant to both fungicides (67%), resistant only to thiophanate-methyl (14%), and resistant only to vinclozolin (2%). Isolates resistant to at least one fungicide were found in 33 of the 35 locations from which samples were taken. Disease incidences on geranium seedlings treated with 600 μg/ml of thiophanate-methyl and then inoculated with isolates sensitive and resistant to this fungicide were 1.4 and 96.1%, respectively. Disease incidences on geranium seedlings treated with 600 μg/ml of vinclozolin and then inoculated with isolates sensitive and resistant to this fungicide were 0.3 and 91.9%, respectively. With thiophanate-methyl, correlation coefficients (r) between disease incidence and log EC50-germ or log EC50-growth were 0.987 and 0.992, respectively. With vinclozolin, correlation coefficients between disease incidence and log EC50-germ and log EC50-growth were 0.975 and 0.893, respectively. Correlation coefficients between the two EC50 values for thiophanate-methyl were 0.989 and for vinclozolin were 0.900. Isolates sensitive to thiophanate-methyl had a mean EC50-germ value of 0.93 μg/ml and a EC50-growth value of 0.11 μg/ml. For isolates sensitive to vinclozolin the mean EC50-germ value was 1.63 μg/ml and the mean EC50-growth value was 0.26 μg/ml. Thiophanate-methyl-resistant isolates had mean EC50-germ and EC50-growth values greater than 500 μg/ml while vinclozolin-resistant isolates had a mean EC50-germ value greater than 500 μg/ml and a mean EC50-growth value of 3.18 μg/ml.

Efficacy of four fungicides with different modes of action (vinclozolin, pyrimethanil, benomyl and fenhexamid) in control of B. cinerea in raspberry, was investigated in the paper. The trials were conducted at two localities in commercial raspberry plantations. In the case of unsatisfactory fungicide efficacy, qualitative and/or quantitative test of the susceptibility of the isolates to particular fungicide was performed, to determine whether the low efficacy is a consequence of resistance development in the pathogen population. At both localities, pyrimethanil and fenhexamid demonstrated the highest efficacy (73.2-89.6%), while the efficacy of vinclozolin was statistically significantly lower (48.7-63.4%) at both localities. However, qualitative and quantitative test of susceptibility to vinclozolin showed that all the isolates were susceptible to vinclozolin and that the reason for unsatisfactory efficacy should be primarily sought in inadequate fungicide application.

Vinclozolin (VCZ), an antiandrogenic fungicide, is an endocrine disrupting chemical that is known to possess high affinity for the androgen receptor (AR) and modulate expression of critical androgen-dependant genes in the prostate. In this study, viability and expression of AR, NKX3.1 and CYP3A4 genes were measured in androgen-sensitive prostate cells LNCaP after exposure to VCZ and VCZ treated with S9 microsomes in a time and dose dependent manner. NKX3.1 is an androgen regulated gene that plays a vital role in prostate development. CYP3A4 is involved in xenobiotic metabolism. VCZ decreased the viability at high doses after 48 hours which was slightly mitigated by treatment with S9 metabolites. Expression of NKX3.1 and CYP3A4 was upregulated while an initial downregulation of AR was observed. NKX3.1 upregulation corroborates with possibility of antiandrogens to act as androgens in LNCaP. The results illustrate that VCZ can interfere with the expression of critical prostate genes.

Les polluants environnementaux, en particulier les perturbateurs endocriniens (PE), agissent à très faibles doses sur des cibles multiples. Les effets rapportés portent en majorité sur les organes de reproduction. Très peu d'études ont porté sur le squelette alors que le cartilage et l'os sont sous un puissant contrôle hormonal, depuis le stade fœtal où le système hormonal se met en place jusqu'au vieillissement, en passant par la naissance (hormones thyroïdiennes, hormone de croissance), la puberté et la ménopause chez la femme (stéroïdes sexuels). L'objectif de ce travail est d'étudier les effets de polluants anti-androgènes (vinclozoline, V et métabolite actif M2) ou xenestrogènes (génistéine, G; bisphénol A, BPA), in vivo sur le développement du squelette du rat Wistar et in vitro sur les marqueurs de différenciation chondrogéniques. Les effets in vivo ont été étudiés à des doses inférieures aux "No Observed Adverse Effect Levels " (NOAEL) fixés par les instances européennes (EFSA) et internationales (US EPA). Des rattes ont été exposées à V, G seuls, combinés (GV) et/ ou associés au BPA (BGV), et ce de la conception des petits jusqu'à leur sevrage (J30) ou leur sacrifice (J30, J110). Les effets ont été recherchés sur des petits de mères et portées différentes, quatre pour chaque traitement, âge et sexe. Les effets in vitro du métabolite M2 de la Vinclozoline, associé ou non avec G et BPA, ont été étudiés sur l'expression de marqueurs chondrogéniques en utilisant : 1) un modèle murin de cellules souches inductibles vers la voie chondrogénique (C1) pour les effets sur la différenciation chondrogénique précoce et 2) des chondrocytes de souriceaux nouveau-nés, différenciés en culture primaire ou dédifférenciés (passages répétés). Comparaison avec les effets du bFGF, facteur de dédifférenciation chondrogénique. Résultats : In vivo, l'exposition à V, seule ou associée à G ou au BPA induit chez les rattes F1 exposées, une cannelure de la queue, discrète mais perceptible à la palpation en regard de chaque articulation intervertébrale. Les xénestrogènes tendent à réduire cet effet de V. Les rats et les animaux F2 ne sont pas atteints. L'examen par micro CT-scan montre une augmentation significative de la largeur des apophyses transverses (ITA) des vertèbres, et une diminution de la hauteur des corps vertébraux chez les rattes F1 exposées en regard des contrôles. Ces modifications anatomiques rappellent certaines pathologies génétiques des collagènes (dysplasies épiphysaires) chez l'homme Elles sont absentes chez les rats F1 et les animaux F2. Elles sont en partie transitoires car présentes à J30 (effets sur ITA et longueur) quand seul l'effet sur l'ITA perdure à J110. L'examen histologique des cartilages de croissance des corps vertébraux montre un déséquilibre entre les zones de prolifération et d'hypertrophie qui évoque une modification de la maturation du cartilage de type estrogénique. Ces effets sont ici aussi transitoires et majoritairement observés chez les rattes. L'effet plus prononcé du BPA lisse toutes les autres activités. Cela suggère que les PE pourraient moduler la différenciation du cartilage de croissance. C'est ce qui a été étudié in vitro. In vitro. Le premier objectif était d'évaluer les effets des PE sur la dynamique d'induction chondrogénique (cellules C1). Nous montrons que l'addition de M2 seul ou avec G ou BPA modifie le processus de maturation du collagène2 sans effet sur les autres marqueurs (SOX9, Agrécane, Col10). M2 prolonge l'expression de COL2A immature et retarde son remplacement par l'isoforme COL2B. Le second objectif était d'étudier les effets des PE sur la régulation de l'expression de COL2A au cours du processus de dé-différenciation des chondrocytes in vitro. L'expression de COL2A augmente avec le degré de dédifférenciation cellulaire (passages successifs) et double en présence de M2, G et BPA. Cet effet dépend des récepteurs aux estrogènes (ER) et des voies p38-MAPK. (...)

Substanzen, die durch ihr hormonell wirksames Potenzial mit dem Hormonsystem interagieren und adverse Effekte auf die Reproduktion von Invertebraten und Vertebraten ausueben koennen, erlangten in den letzten Jahrzehnten große Aufmerksamkeit. Viele dieser Substanzen reduzieren die Fertilitaet oder die Fekunditaet, fuehren zu Abnormalitaeten in der Ontogenese oder im Verhalten der Tiere und haben Einfluss auf die Geschlechterverhaeltnisse. In der vorliegenden Arbeit wurden verschiedene Aspekte dieses Themengebietes bearbeitet. Das in Europa endemisch vorkommende Rotauge (Rutilus rutilus), ein Sueßwasserfisch, wurde als Modelltier fuer den Nachweis von (anti)androgenen Effekten auf aquatisch lebende Organismen etabliert. Zum Nachweis der (anti)androgenen Wirkmechanismen wurden die Tiere mit Modellsubstanzen aus drei verschiedenen Gruppen exponiert. Aus der Gruppe der Substanzen mit potenziell androgener Wirkung wurden Triphenylzinn (TPT) und Methyltestosteron (MT) verwendet, aus der Gruppe der Antiandrogene Vinclozolin (VIN) und Cyproteronazetat (CYP) und aus der Gruppe der Aromatasehemmer, und somit potenziell androgener Wirkung, Letrozol (LET) und Fenarimol (FEN). Feedbackmechanismen auf die Hypothalamus-Hypophysen-Gonaden-Achse (mRNA-Expression des Luteinisierenden Hormons, des Follikel stimulierenden Hormons und der Aromatase), mRNA-Expression potentieller Biomarker in der Leber (Androgen-Rezeptor-mRNA, Oestrogen-Rezeptor-mRNA), Sexsteroidspiegel im Blutplasma (17beta-Oestradiol und 11-keto-Testosteron), Enzymaktivitaeten im Gehirn (Aromatase), Histologie der Gonaden, Totallaenge, Gewicht und Geschlechterverteilung wurden als Endpunkte analysiert, um adverse Effekte auf die Reproduktionsbiologie von R. rutilus zu zeigen. Die untersuchten Endpunkte eigneten sich sehr gut zum Nachweis verschiedener Wirkmechanismen.
Substances that are able to interact with the endocrine system and cause adverse effects on the reproduction of invertebrates and vertebrates have gained much attention over the last few decades. Many of these substances reduce fertility or fecundity, lead to developmental abnormalities or abnormalities in the behaviour of animals and have an impact on sex ratios. The present study examines various aspects of these topics. The roach (Rutilus rutilus), a freshwater fish endemic in Europe, was established as a model animal for the detection of (anti)androgenic effects on aquatic organisms. For examination of the (anti)androgenic action, the animals were exposed to model compounds from three different groups: triphenyltin (TPT) and methyltestosterone (MT) from the group of substances with potentially androgenic effect, vinclozolin (VIN) and cyproteronacetate (CYP) from the group of antiandrogens, and letrozol (LET) and fenarimol (FEN) from the group of aromatase inhibitors, which thus have a potentially androgenic effect. Feedback mechanisms on the hypothalamus-pituitary-gonad-axis (mRNA expression of luteinising hormone, follicle stimulating hormone and aromatase), mRNA expression of potential biomarkers in the liver (androgen receptor mRNA, oestrogen receptor mRNA), steroid levels in the blood plasma (17beta-oestradiol and 11-ketotestosterone), enzyme activity in the brain (aromatase), histology of the gonads, total length, weight and sex ratios were analysed as endpoints to show adverse effects on the reproductive biology of R. rutilus. The studied endpoints are suitable for the detection of different modes of action. The histological examination of the gonads proved to be especially sensitive with the exposure to AACs to resulting in fundamental adverse damages to the gonads. It was ascertained that - in the early stages of ontogeny - androgens play as crucial of a role in the development of the gonads as previously attributed primarily to oestrogens.

Notre environnement contient de plus en plus de polluants dont les perturbateurs endocriniens (PE), associés à une augmentation de la prévalence de pathologies graves et à l'émergence de nouvelles pathologies. Récemment, une nouvelle pathologie amélaire appelée hypominéralisation des molaires et des incisives (MIH) a été décrite. Cette pathologie, dont l'étiologie est inconnue, est devenue un véritable problème de santé publique avec une prévalence d'environ 18%. L'objectif de ce travail fut de rechercher des relations potentielles entre l'exposition aux PE et le MIH. Pour cela, des rats Wistar ont été exposés à de faibles doses de trois PE, le bisphénol A (BPA), la génistéine et la vinclozoline, seuls ou en association, de la conception jusqu'au sacrifice. 75% des rats traités au BPA seul, présentaient des taches d'hypominéralisation amélaire dont les caractéristiques structurales et biochimiques étaient comparables à celles des dents humaines atteintes par le MIH analysées en parallèle. Ainsi, nous proposons d'utiliser les dents MIH comme biomarqueur précoce d'exposition aux PE agissant comme le BPA. Par ailleurs, nos résultats ont montré que l'action du BPA sur la prolifération des précurseurs améloblastiques et les modulations d'expression de deux gènes cibles clé, l'énaméline et la kallikréine 4, ne semble emprunter qu'en partie la voie œstrogénique suggérant que dans l'épithélium dentaire, le BPA interagit avec d'autres récepteurs que ERα et ERß. La combinaison du BPA avec les deux autres PE impacte apparemment moins l'amélogenèse. Les trois PE étudiés ici modulent chacun différemment l'expression des gènes codant les protéines matricielles amélaires et les protéases spécifiques de l'émail, réduisant l'effet des autres PE. Ceci explique, au moins en partie, l'impact différentiel sur l'émail de substances exogènes hypominéralisantes dont la relation avec le développement de certaines pathologies sera intéressante à étudier dans le futur
Our environment has become increasingly contaminated by pollutants including endocrine disruptor Chemicals (EDCs), associated with an increased prevalence of serious diseases and the emergence of new diseases. Recently, a new dental pathology called molar incisor hypomineralization (MIH) has been described. This pathology, whose etiology is unknown, has become a real public health problem with a prevalence of roughly 18%. The aim of this work was to investigate potential relationships between exposure to EDCs and MIH. For this purpose, Wistar rats were treated from the conception to the sacrifice, with low doses of three EDCs, bisphenol A (BPA), genistein and vinclozolin, alone or in combination. 75% of rats treated with BPA alone have shown enamel hypomineralized spots sharing similar biochemical and structural characteristics with human teeth affected by MIH analyzed in parallel. Thus, we propose to use MIH teeth as an early biomarker o exposure to EDCs acting as BPA. The effects of BPA on pre-ameloblast prolifération and enamelin and klk4 expression seem to use the estrogenic pathway only in part suggesting that BPA could interact with other receptors than ERa and ERp in dental epithelial cells. Each combination of BPA with other EDCs affects specifically the amelogenesis explaining the lower impact of the combination compared with BPA alone. This explains, at least in part, the différentiel impact of exogenous hypomineralizing substances on enamel whose relationship with the development of certain diseases will be interesting to study in the future

L'iprodione est transformee par voie chimique et par voie microbiologique dans les sols. La transformation microbiologique de ce fongicide est minoritaire dans les sols non adaptes et majoritaire dans les sols adaptes. Elle entraine l'hydrolyse au niveau de la fonction uree de la chaine laterale du cycle dicarboximide de l'iprodione conduisant au n-(3,5-dichlorophenyl)-2,4-dioxoimidazolidine: metabolite (ii). Ce metabolite subit ensuite une ouverture du cycle dicarboximide pour conduire a l'acide 3,5-dichlorophenyluree acetique: metabolite (iii). L'hydrolyse du metabolite (iii) conduit a la formation de la 3,5-dichloroaniline. Trois souches bacteriennes impliquees dans la degradation de l'iprodione ou de ses metabolites ont ete isolees. Pseudomonas sp. Et pseudomonas fluorescens degradent l'iprodione en metabolite (ii) et dans certaines conditions le metabolite (ii) en metabolite (iii). Pseudomonas paucimobilis degrade successivement le metabolite (ii) en metabolite (iii) puis en 3,5-dichloroaniline. Le denombrement de la souche d'arthrobacter par marquage immunofluorescent a montre que la proliferation de cette souche est une des causes de la degradation acceleree de l'iprodione dans un sol adapte. La vinclozoline est microbiologiquement degradee en 3',5'-dichlorophenyl-2-hydroxy-2-methylbut-3-enanilide et en 3,5-dichloroaniline ou chimiquement hydrolysee en enanilide et en acide n-(2-hydroxy-2-methyl-1-oxobuten-3-yl)-3,5-dichlorophenyl-1-carbamique. Une souche appartenant au genre corynebacterium ou a un genre voisin degrade l'acide n-carbamique en enanilide et en compose d non identifie mais sa capacite a degrader la vinclozoline n'a pas pu etre clairement demontree. Un sol adapte a la vinclozoline degrade l'iprodione de facon acceleree mais l'inverse n'a pas ete observee. Ces deux fongicides presentent donc un phenomene d'adaptation croisee dans un seul sens

In the last two decades, there have been growing scientific concern, public debate, and media attention over the possible deleterious effects in humans and wildlife that may result from exposure to substances that have the potential to interfere with the endocrine system. Endocrine disrupting compounds (EDCs) encompass a variety of substance classes, including natural and synthetic hormones, plant constituents, pesticides, substances used in industry and in consumer products, pollutant. It is well documented that EDCs targets are mainly the nuclear receptors (NRs) such as the sexual hormones estrogen receptors ERs. ER is involved in a broad spectrum of physiological processes in different organs and tissues as well as in several diseases, such as breast and endometrial cancer, osteoporosis, and prostate hypertrophy, neurodegenerative diseases or in immune system activation. The regulatory agencies for the protection of human health and wildlife have been issuing the necessity to investigate and clarify the mode of action of these exogenous substances by the development of alternative toxicological methods such as in silico model and in vitro testing in order to predict the toxicity of these EDCs. This research had the ambitious aim to develop an integrated toxicological strategy based on the combination of available information of endocrine disrupting activity retrieved from the scientific literature, in silico model, imaging methodologies applied to reporter systems in vitro and in vivo and ex vivo to predict among a set of chemicals those with an endocrine disrupting activity or ability to activate other toxicological pathways such as inflammation and oxidative stress measured in the male reproductive organs and in the genital and abdominal area of mice. The selected molecules range from known (DES) to suspected (BPA) endocrine disruptors and included both synthetic (DEHP) and natural (genistein) compounds. The first step used was in silico analysis with evaluation of the possible binding of selected substances to the estrogen alpha receptor to support the hypothesis that their hormonal activity occurred through a receptorial mechanism. This approach is commonly used and is also part of the first level of investigation suggested by EFSA/ECHA in the recognition of EDCs. The computational methodology estimated different values of affinity of each ligand to hER Ligand Binding Domain (LBD). The use of two different approaches (XP GLIDE SCORE and MMGBSA dG Bind) also allowed for solvation to be taken into account. That meant that MMGBSA protocol considered both the interactions of some water molecules with the LBD and the solvent-ligand ones. The estradiol showed the best affinity values in both approaches as being the endogenous hormone was able to contrast the solvation effect. The dissociation constant (Ki) values calculated from the XP GLIDE SCORE fitted well with the Ki experimentally determined in vitro binding assay by other research groups. Thus, the computed Ki has been chosen as parameter for the prediction of putative endocrine disruptor activity. However, the lack of correlation between the (computed and experimental) Ki and in vivo experimental observed ED activity (from literature data) for all chemicals (only estradiol and zearalenone have similar affinity to ER and literature evidences of ED activity; genistein has a good Ki values but not ED activity such as BPA and methoxychlor), did not allow a prioritization of the investigated chemicals for ED activity through the results of their affinity. In the next step, to check if the receptor binding well correlated with the hormonal activity, the ER Reporter gene assay was performed, based on the ability of a compound to stimulate ER-dependent transcriptional activity in genetically engineered mammalian cells. The cell lines are MCF-7 cells which express human endogenous ERα. The cells are transformed (transfected) by introducing vectors containing DNA sequences for the receptor, along with EREs linked to a reporter gene, and the reporter gene itself. The reporter gene used in human cancer cells usually codes for luciferase (CALUX, chemically activated luciferase expression). In the transactivation the EDCs show their estrogenic potency calculated as EC50, in respect to the positive control, 17β-estradiol. This system has enabled us to evaluate the kinetic and the biological consequences of cellular activation in the same cell monolayer by bioluminescence imaging of photon emissions that were pictures of activated ER status at 6 and 48 hours after the initial treatments. From this in vitro assay three factors were taken into consideration, power, efficacy and trend over time. The in vitro dynamic ER activation showed that for some chemicals (genistein, BPA, methoxychlor), the potency (EC50) and the efficacy (fold induction) changed over time, but not for others (estradiol, zearalenone and DES). Considering that estradiol, zearalenone and DES certainly have an activity in the animal and in man as endocrine disruptors, the duration of effect parameter combined with power and efficacy were likely to be associated in predicting the activity. Together with receptor affinity and the ability to induce a biological response, it also seemed relevant how long the response was lasting. By consequence, the combination of the variation of the potency response and the efficacy, “normalized” respect to the efficacy values quantify at 48 hours, was successfully used in discriminating positive and negative compounds for their endocrine disrupting activity. By means of this analysis 17β-estradiol, DES and zearalenone were put at the top of the list (also supported by their known ED activity), genistein resulted to represent a putative threshold of no-concern for ED effect, in supporting published data, while methoxychlor and BPA were definitely not considered a priority in terms of ED activity. This in vitro classification fitted well with the in silico outcomes, since the strongest estrogen receptor binders were ranked in the first positions (17β-estradiol, DES and zearalenone). Besides, was no possible to calculate EC50s for 4-nonylphenol, DEHP and vinclozolin, not making possible to classify them as ED, totally in agreement with in silico results and in line with literature data (vinclozolin is mainly an androgen antagonist). The third step of our stepwise approach was intended to verify in vivo the interaction of selected chemicals with the estrogen receptor and in addition the activation of their pathways triggering primary harmful effects. We used three reporter mice designed in order to evaluate the effect of selected compounds to activate ER and causing oxidative stress and inflammation. We have chosen to test zearalenone (well-known endocrine disruptor and clearly identified as such by our in silico-in vitro approach), and BPA for which there are controversial data in the literature and that our approach has negatively classified as ED. In our experiments zearalenone showed to be active on ER pathway in the abdominal area and significantly activated the inflammatory pathway in the genitals (in this specific case in the prostate, result of ex vivo bioluminescence analysis). These results were perfectly in line with the literature reports, in which prostate inflammation and metaphase were detected in both mice and rats. Bisphenol A did not produce a significant activation in both the areas and in the ex vivo analysis, again in agreement with in silico/in vitro results. We used a combination of innovative approaches that led to a conclusion that in silico screening cannot be used as a stand-alone procedure due to its intrinsic lack of biological meaning, although it can be successfully used as a first prioritizing step in a tier approach. The second mandatory check for the in silico positive hits should be an in vitro evaluation procedure, in which the affinity of the positive hits is measured through a reference cellular assay. Our results showed that integrating the time variable in the evaluation of the potency, the tested compounds could be classified as ED or no-ED. The in vivo experiment highlighted that a potent estrogenic compound, as zearalenone, could also raise concern for the activation of other toxicological pathway such as the inflammatory ones. We are aware that this indication of procedure must be evaluated and validated on dozens of molecules whose in vivo activity is already known before arriving at its use to predict the possible activity of ED of unknown molecules, but we think that this approach deserves to be implemented.

L'incidence de cancers hormono-dépendants ne cesse d'augmenter dans les pays occidentaux ; une infertilité accrue et des anomalies du système reproducteur ont également été notées dans ces mêmes pays. L'hypothèse a été émise selon laquelle des composés faisant partie de notre environnement, appelés perturbateurs endocriniens (PE), pourraient être liés à ces phénomènes. Afin d'évaluer le risque de PE sur le développement de la glande mammaire, nous avons développé un modèle original d'exposition, où un phyto-œstrogène de soja (génistéine) et un fongicide anti-androgénique retrouvé dans les légumes et les fruits (vinclozoline), sont administrés à de faibles doses (1 mg/kg/jour) chez le rat. Nous avons mis en avant que l'exposition in utero et pendant la lactation à ces composés altère le développement de la glande mammaire chez les animaux pubères [augmentation du branchement et de prolifération épithéliale, hyperplasie ductale et changement de la réceptivité hormonale] ainsi que chez les animaux cycles [augmentation de la surface mammaire et développement des structures lobulo-alvéolaires sécrétrices]. L'analyse transcriptomique montre que cette exposition in utero altère également le profil d'expression génique de la glande mammaire ; ces altérations moléculaires sont compatibles avec les modifications histologiques. Par ailleurs, l'exposition du sevrage jusqu'à l'âge adulte à la génistéine et à la vinclozoline induit des altérations morphologiques de la glande mammaire des animaux adultes. Ce travail apporte de nouvelles connaissances concernant les effets d'un androgène/anti-androgène sur le développement de la glande mammaire chez la femelle. Cette étude montre pour la première fois que l'exposition à un mélange de deux perturbateurs endocriniens, appartenant à deux familles différentes, perturbe le développement de la glande mammaire chez le rat femelle. Les conséquences d'une exposition au mélange apparaissent plus sévères comparées à celles observées avec les molécules isolées, ce qui souligne le risque de la multi-exposition
The incidence of hormone-dependent cancers is increasing in Western countries; increased infertility and reproductive abnormalities were also noted in these same countries. This has raised the hypothesis that compounds found in our environment, called endocrine disruptors (EDs), could be related to these pathologies. This thesis aims at identifying the effects and mechanisms of EDs on the development of rat mammary gland following the administration of two xeno-hormones having distinct endocrine properties: genistein (soy phytoestrogen with major estrogen receptor affinity) and vinclozolin (anti-androgenic fungicide found in vegetables and fruit). The particularises of this project were: 1) a study following in utero and gestational exposure at peri-pubertal period (PND35 and PND50); 2) a long life exposure study on adult rats; 3) doses relevant overall human exposure (1 mg/kg/day). We show that exposure in utero and during lactation to these compounds alter the development of the mammary gland in pubertal animals [increase in branching and epithelial proliferation, ductal hyperplasia and changes in hormonal receptivity] and in cycled animals [increase of the mammary gland area and development of lobulo-alveolar structures]. Using a transcriptomic approach, we also evaluated gene expression changes in mammary gland. Molecular changes are dependent on the period of postnatal development and the compound considered. The molecular data concerning in utero and lactational exposure are consistent with the histological observations. Furthermore, exposure from weaning to adulthood induces different alterations of the mammary gland at adulthood. In summary, this work provides new observations on the effects of a chemical anti-androgen on the development of the mammary gland in females. These studies also show for the first time that exposure of a mixture of two endocrine disruptors, belonging to two different families, disrupts the development of the mammary gland in female rats with more severe effects compared to those observed with the isolated molecules; these results highlight the risk of multiple exposure

Cette etude analytique a ete orientee sur trois pesticides, l'iprodione, la vinclozoline et la cymoxanil, couramment employes dans le cadre de la production des framboises et des laitues de la region rhone-alpes. Nous presentons la mise au point de methodes d'analyse repetables et reproductibles avec une comparaison sur les dosages effectues en chromatographies en phase liquide sur colonne (clhp) et sur couche mince (ccm) ainsi qu'en phase gazeuse (cpg). Nous avons suivi l'evolution de la disparition de ces trois fongicides sur les framboises et les laitues traitees selon differentes modalites. Il ressort de notre etude que la cinetique de disparition de l'iprodione et de la vinclozoline suit un modele de pseudo-premier ordre. Par ailleurs, les parametres meteorologiques et agronomiques ont une influence sur le devenir des residus de pesticides

Les glandes salivaires sont des glandes mixtes : la salive (produit exocrine) estimpliquée dans le maintien de l'homéostasie buccale alors que les secrétions endocrines (ex :facteurs de croissance) ont un rôle physiologique (gamétogénèse, ostéogenèse,hypertension...) Chez les mammifères, elles affichent un dimorphisme sexuel qui laisseentrevoir une sensibilité éventuelle à des xeno-hormones.Ce mémoire présente l'action de la génistéine (phyto-oestrogène) et/ou de la vinclozoline(anti-androgène) sur la glande submandibulaire (SM) de rat lors d'une exposition précoce viala mère (gestation-lactation) et lors d'une exposition pendant la période de croissance (dusevrage à l'âge adulte). Les glandes SM, prélevées au stade immature et jeune adulte, ont faitl'objet d'une analyse histologique et d'une étude de marqueurs moléculaire des fonctionsendocrines et exocrines associées aux processus gustatifs. L'exposition précoce ralenti ledéveloppement de la glande SM et augmente sélectivement la préférence au sucré des malesimmatures mais pas des adultes ; l'analyse moléculaire révèle une action sélective sur lesfonctions exocrines corrélée à celle sur les préférences, ainsi qu'une action sur les fonctionsendocrines (facteurs de croissances) qui s'inverse avec l'âge. L'exposition à partir du sevrageperturbe seulement les mâles qui présentent des altérations des structures sécrétrices coupléesà des modifications d'expression des récepteurs hormonaux et facteurs de croissance, maisaussi au taux sérique de l'EGF.Cette étude identifie la glande submandibulaire comme cible de perturbateurs endocriniens etpose la question des conséquences physiologiques à terme