Academic literature on the topic 'Mitotic and apoptotic index of liver cells'

The aim of this study was to study the effect of combined MMSC and HSC transplantation on liver regeneration under conditions of toxic carbon tetrachloride damage. Materials and methods. The study was performed on white male mice with toxic liver damage by intraperitoneal administration of carbon tetrachloride at a dose of 50 µl per mouse once. An hour after modeling liver damage, placental MMSCs and HSCs were administered intravenously at a dose of 4 million cells/kg and 330 thousand cells/kg, respectively, suspended in 0.2 ml of 0.9% NaCl solution. Control group animals were given 0.9% NaCl solution-0.2 ml intravenously. On days 1, 3, and 7 after cell transplantation, changes in inflammatory activity in the liver were evaluated, and mitotic and apoptotic indices were determined. On the 7th day after the introduction of cells, the activity of DNA repair enzymes of the PARP family was analyzed. Results. Combined MMSC and HSC transplantation leads to a decrease in the index of inflammatory activity in the liver due to a decrease in necrosis, hepatocyte dystrophy, and a decrease in infiltration. As a result of the study, an increase in the activity of PARP repair enzymes was found, which led to a decrease in programmed cell death. Also, cotransplantation of MMSCs and HSCs was accompanied by increased mitotic activity of hepatocytes. Conclusion. Cotransplantation of MMSCs and HSCs under conditions of toxic liver damage reduces the inflammatory response, stimulates the mitotic activity of hepatocytes, and increases the activity of enzymes of the DNA repair system. Activation of the liver's reparative system, in turn, reduces the programmed death of hepatocytes.

Objective: to study the cellular mechanisms of activation of regenerative processes in the liver when using total RNA (tRNA) of bone marrow cells (BMCs) based on an extended liver resection (ELR) model. Materials and methods. Male Wistar rats (n = 80) with ELR model (70%) were divided into 2 groups: group 1 (control group) had a single saline injection, while group 2 (experimental group) received a single tRNA injection at a 30 μg/100 g dose of animal weight. The biochemical parameters of liver function and weight were monitored over time. Also monitored were microstructural changes in hepatocytes 48 hours after ELR by examining mitotic activity, caspase-9 expression and morphometric parameters. Results. It was found that in group 2, in comparison to group 1, there was faster normalization of biochemical parameters (by 10–14 days), a higher mitotic index of hepatocytes (23.45‰ versus 5.37‰), and initially sharper decrease and then faster recovery of liver mass (by 10–12 days versus 18–20 days). Both groups showed almost total expression of caspase-9, including in mitotically splitting hepatocytes. Group 1 demonstrated decreased values of morphometric parameters of single and binuclear cells, decreased number of binucleated hepatocytes and increased total density of hepatocytes as compared to the intact liver. Intraperitoneal administration of tRNA increased morphometric parameters of mononuclear hepatocytes, did not affect their number, but increased the area of the nuclei of binuclear hepatocytes as compared to the control group. Conclusion. The proven capability of cell-bone marrow total RNA to simultaneously support apoptosis in liver cells after ELR and induce mitotic activity indicates that tRNA can switch activated apoptosis to cell proliferation at the early phase of the regenerative process. This effect may be due to the presence of regulatory RNA molecules in tRNA, including numerous non-coding RNAs.

Abstract Iron overload increases the mitotic index in rat hepatocyte cultures stimulated by EGF. Iron, implicated in tumoral cell proliferation, promotes the development of the hepatocellular carcinoma. Conversely, iron chelation decreases cell proliferation. Polyamines play also an important role in cell proliferation. The purpose of the present work was to compare the effect of the two oral iron chelators ICL670A and CP20 on cell proliferation, apoptosis and polyamine metabolism in rat and human liver cell cultures. We used three experimental models: the rat hepatoma cell line FAO, the rat liver epithelial cell line RLEC and the human hepatoma cell line HUH7. Chelator cell uptake was analyzed by mass spectrometry. DNA replication and cell viability were measured by thymidine incorporation and mitochondrial succinate dehydrogenase activity. Cytotoxicity was evaluated by extracellular LDH activity. Cell cycle analysis was performed by flow cytometry. Apoptosis was quantified by DNA fragmentation and caspase 3 activity. Polyamine metabolism was analyzed by measuring their intracellular concentrations by mass spectrometry as well as the ornithine decarboxylase (ODC) and spermine-spermidine acetyl transferase (SSAT) mRNAs levels. ICL670A entered the cells four times better than CP20. We observed that ICL670A (20 μM) decreased DNA replication (−75%) and cell viability (−40%) while a comparable CP20 stoechiometric concentration (30 μM) had no significant effect. ICL670A exhibited also a higher cytotoxicity than CP20. The decrease in DNA replication induced by ICL670A was correlated to a cell cycle block in S phase; CP20 (30 μM) increased slightly the cell number in G2/M phase while a higher CP20 concentration (150 μM) blocked clearly cell cycle in G2/M phase. By measuring DNA fragmentation and the activity of the executioner caspase 3, we demonstrated a high apoptotic effect of ICL670A (20 μM) compared to CP20 (30 μM). In the HUH7 human cell line, we observed that ICL670A (20 μM) decreased the intracellular levels of polyamines which was correlated to a drop in ODC and SSAT mRNAs levels. Conversely, an increase in SSAT mRNA level was observed in the presence of CP20 (150 μM) leading to an enhancement of putrescine and spermidine levels. In conclusion, ICL670A and CP20 inhibit cell proliferation by two distinct ways. ICL670A compared to CP20: enters better the cells; exerts a higher antiproliferative and apoptotic effect; modulates polyamine metabolism by inhibiting ODC and SSAT enzyme activities.

Thyroid hormone is known to elicit diverse cellular and metabolic effects in various organs, including mitogenesis in the rat liver. In the present study, experiments were carried out to determine whether thyroid hormone is able to stimulate cell proliferation in another quiescent organ such as the pancreas. 3,5,3′-l-tri-iodothyronine (T3) added to the diet at a concentration of 4 mg/kg caused a striking increase in nuclear bromodeoxyuridine (BrdU) incorporation of rat acinar cells 7 days after treatment (the labeling index was 46.7% in T3-treated rats vs 7.1% in controls). BrdU incorporation was limited to the acinar cells, with duct cells and islet cells being essentially negative. The increase in DNA synthesis was accompanied by the presence of several mitotic figures. Histological examination of the pancreas did not exhibit any sign of T3-induced toxicity. Determination of the apoptotic index, measurement of the serum levels of α-amylase and lipase, and glycemia determination did not show any increase over control values, suggesting that the enhanced proliferation of acinar cells was a direct effect induced by T3 and not a regenerative response consequent to acinar or β-cell injury. Additional experiments showed that DNA synthesis was induced as early as 2 days after T3 treatment (the labeling index was 9.4 vs 1.9% in controls) and was associated with increased protein levels of cyclin D1, cyclin A and proliferating cell nuclear antigen, with no substantial differences in the expression of the cyclin-dependent kinase inhibitor p27. The mitogenic effect of T3 on the pancreas was not limited to the rat, since extensive acinar cell proliferation was also observed in the pancreas of mice treated with T3 for 1 week (the labeling index was 28% in T3-treated mice vs 1.8% in controls). Treatment with three other ligands of nuclear receptors, ciprofibrate, all-trans retinoic acid and 1,4-bis[2-(3,5-dichloropyridyloxy)]benzene, induced little or no pancreatic cell proliferation. These results demonstrated that T3 is a powerful inducer of cell proliferation in the pancreas and suggested that pancreatic acinar cell proliferation by selected agents may have potential for therapeutic use.

Abstract Depending on timing and dose, exogenous glucocorticoids induce a wave of apoptosis in the adult rat anterior pituitary, a response that is enhanced by adrenalectomy. In this study, we show that the size of the glucocorticoid-sensitive apoptotic population progressively increases during the week following surgical adrenalectomy, plateaus for a further week, then spontaneously declines to levels seen in intact animals by 4 wk. Mitotic activity, in contrast, rises rapidly post adrenalectomy but returns to baseline within 2 wk. Increased mitotic activity precedes the increase in the population of cells that undergo glucocorticoid-induced apoptosis and the subsequent decline in mitotic activity precedes the decline in apoptotic sensitivity despite persistent elevation of hypothalamic CRH and pituitary proopiomelanocortin transcripts. If glucocorticoid exposure is delayed until 4 wk post adrenalectomy when the apoptotic response has returned to baseline, glucocorticoid withdrawal, by transiently increasing mitotic activity, again primes the formation of an expanded glucocorticoid-sensitive apoptotic cell population. These data suggest that apoptotic sensitivity is largely confined to cells that have recently entered the cell cycle. This observation is further corroborated by demonstrating an abrupt glucocorticoid-induced step-down in the bromodeoxyuridine-labeling index to basal levels in rats given daily injections of bromodeoxyuridine during the week following adrenalectomy.

Abstract Abstract 4967 Rituximab-chemotherapy relapsed/refractory (r/r) B-cell lymphomas represent an emerging clinical challenge that underlies the need to develop alternative therapeutic strategies. A better understanding of the mechanism(s)-of-action of BTZ and other proteasome inhibitors (PI) is likely to aid in the identification of biomarkers that can be used to determine clinical responsiveness and/or help in the rational development of novel PI-based therapeutic combinations (e.g. incorporating biologics, small molecules and/or chemotherapy) in r/r B-cell lymphoma. Previously we demonstrated that rituximab resistance was associated with increased proteasome activity leading to a de-regulation in the apoptotic threshold of lymphoma cells to multiple chemotherapy agents. Pharmacological and genetic (e.g. siRNA silencing of BAK/BAX) inhibition of apoptosis partially affected BTZ activity in rituximab-resistant (RSCL) but not in rituximab-sensitive cell lines (RSCL) suggesting the existence of alternative pathways of cell death associated with PI exposure. To this end we evaluated the contribution of cellular senescence, cell cycle inhibition, or mitotic catastrophe to the anti-tumor activity of BTZ as a single agent or in combination with chemotherapeutic agents in RSCL, RRCL and in primary tumor cells. Lymphoma cells were exposed to BTZ (10-25nM) for 24–48 hrs. Cell senescence was determined by SA-β-gal staining using a senescence assay kit and inverted phase-contrast microscopy was performed. Changes in cell cycle were analyzed by the FACScan DNA method and changes in cell cycle regulatory proteins (i.e. cdc2, cyclinA/B, p21, CDK2/4/6) were analyzed by Western blotting. Mitotic index was determined by Wright-Giemsa stain and positive cells were counted under a Nikon microscope. Mitotic catastrophe was determined by confocal microscopy by staining with α-tubulin antibody. Finally, changes in ATP content was determined by the Cell Titer Glo assay. Baseline differences were observed between RSCL and RRCL in terms of cell morphology, proliferation rate and senescence. RRCL (Raji2R and Raji4RH) were considerably larger in size, had a slower proliferation rate and an exhibited a 3-fold increase the number of cells in senescence than RSCL. In vitro exposure of RSCL and RRCL to BTZ attenuated the number of cells in senescence by 50–75%. Cell cycle analysis demonstrated that RRCL had more cells in S phase when compared to RSCL. In vitro exposure to BTZ-induced G2/M arrest in RRCL, but not in RSCL. Overexpression of G2/M cell cycle regulatory proteins cyclin B and cdc2 were observed in RRCL and in tumor cells isolated from r/r B-cell lymphoma patients. Mitotic catastrophe with multi-nucleated cells were only detected in RRCLs exposed to BTZ. In vitro and ex vivo exposure of RSCL and RRCL to BTZ potentiated the cytotoxic effects of paclitaxel and overcame the acquired resistance to chemotherapy drugs in RRCL and primary tumor cells isolated from r/r lymphoma patients in a dose-dependent manner. Our results suggested that BTZ activates several death pathways in B-cell lymphoma pre-clinical models. In addition to apoptosis, BTZ is capable in triggering mitotic catastrophe in rituximab-chemotherapy lymphoma cells with decreased levels of pro-apoptotic proteins. Moreover, sensitization of RRCL to drug therapy involves interplay between cellular senescence attenuation, G2/M cell cycle regulation, and mitotic catastrophe. Hence, proteasome inhibition may provide a novel therapeutic approach for treating apoptosis-resistant B-cell lymphoma. Research, supported in part as a subproject of NIH grant R01 CA136907-01A1 awarded to Roswell Park Cancer Institute. Disclosures: Hernandez-Ilizaliturri: Genmab: Research Funding; Amgen: Research Funding; Celgene: Consultancy. Czuczman:Millennium: Honoraria, Research Funding.

Melatonin (N-acetyl-5-methoxytryptamine MEL) is an indolamine that has antioxidant, anti-inflammatory and anti-tumor properties. Moreover, MEL is capable of exhibiting both anti-apoptotic and pro-apoptotic effects. In the normal cells, MEL possesses antioxidant property and has an anti-apoptotic effect, while in the cancer cells it has pro-apoptotic action. We investigated the combined effect of MEL and navitoclax (ABT-737), which promotes cell death, on the activation of proliferation in acute promyelocytic leukemia on a cell model HL-60. The combined effect of these compounds leads to a reduction of the index of mitotic activity. The alterations in the level of anti- and pro-apoptotic proteins such as BclxL, Bclw, Mcl-1, and BAX, membrane potential, Ca2+ retention capacity, and ROS production under the combined action of MEL and ABT-737 were performed. We obtained that MEL in combination with ABT-737 decreased Ca2+ capacity, dropped membrane potential, increased ROS production, suppressed the expression of anti-apoptotic proteins such as BclxL, Bclw, and Mcl-1, and enhanced the expression of pro-apoptotic BAX. Since, MEL modulates autophagy and endoplasmic reticulum (ER) stress in cancer cells, the combined effect of MEL and ABT-737 on the expression of ER stress and autophagy markers was checked. The combined effect of MEL and ABT-737 (0.2 μM) increased the expression of protein kinase R (PKR)-like endoplasmic reticulum kinase (PERK), leading to a decrease in the level of binding immunoglobulin protein (BIP) followed by an increase in the level of C/EBP homologous protein (CHOP). In this condition, the expression of ERO1 decreased, which could lead to a decrease in the level of protein disulfide isomerase (PDI). The obtained data suggested that melatonin has potential usefulness in the treatment of cancer, where it is able to modulate ER stress, autophagy and apoptosis.

Abstract The objective of this study was to know the response of supplementation of Phaleria macrocarpa (PM) to adriamycin-cyclophosphamide (AC) in the treatment of C3H mice with breast cancer. Twenty-four C3H mice, who were successfully inoculated with breast cancer cells, were randomly allocated into 4 groups: without treatment, treated with AC, treated with AC + PM 0.07 mg/d, and treated with AC + PM 0.14 mg/d. The tumor size was measured using millimeter calipers before and 12 weeks after treatment. The tumor, liver, and kidneys were removed and prepared for pathologic examination using imunohistochemistry staining, and the apoptotic index was counted using the terminal deoxynucleotidyl transferase dUTP nick end labeling method. AC reduce the tumor growth significantly (P < 0.001), whereas supplementation of PM, which significantly reduced the tumor growth compared with AC only, was at the 0.14 mg/d dose (P = 0.007). AC increase the apoptotic index significantly (P < 0.001), and supplementation with PM showed that the higher dose increased the apoptotic index. The correlation between the apoptotic index and the diameter of tumor was significantly negative (r = −0.884; P = 0.020). The apoptotic index of the liver and kidney increased significantly in the AC group (P < 0.001 and P = 0.002, respectively); supplementation with PM decreased significantly the high apoptotic index caused by AC. We conclude that PM supplementation has a synergic effect to AC treatment in reducing the tumor growth, by increasing apoptosis, and protects the liver and kidney from damage caused by AC.

THE ASSESSMENT OF INFLUENCE OF ZINC IONS AND ECHINACEA PURPUREA (L.) MOENCH FOR MICE INTOXICATED BY CADMIUM IONS Abstract Background. Cadmium (Cd), a well-known environmental hazard, exerts a number of toxic effects in organism. It disturbs the activity of biochemical systems of cells. Accumulation of cadmium depends on the amount of essential trace elements, including zinc. Echinacea purpurea (L.) Moench (EP) can modify its influence. The aim of the study was to assess the influence of ions of cadmium, zinc, and EP on organism in experimental model of mice. The objectives of the scientific work were as follows: 1. To evaluate the accumulation of cadmium in the internal organs of experimental mice after acute and chronic intraperitoneal and per oral intoxication. 2. To assess morphological changes in liver tissue, mitotic and apoptotic activity of liver cells after the intoxication by cadmium ions of different duration and dose. 3. To assess the effect of zinc ions to the accumulation of cadmium in the internal organs and to the mitotic and apoptotic activity of liver cells in the organism of mice intoxicated by cadmium. 4. To evaluate the effect of EP to accumulation of cadmium in internal organs, mitotic and apoptotic activity of liver cells after the chronic intraperitoneal and per oral intoxication by cadmium ions. The scientific novelty of the study. This work makes our knowledge about mechanisms and outcomes of acute and chronic exposure to cadmium deeper. The... [to full text]