Triptolide induces oxidative stress and apoptosis and activates PIK3/Akt signaling pathway in TM4 sertoli cells / 北京大学学报(医学版)

OBJECTIVE@#To investigate the effect of triptolide (TP) on oxidative stress and apoptosis in TM4 sertoli cells and related molecular mechanism.@*METHODS@#TM4 cells were incubated with different concentrations of triptolide for 24 h, then collected for further experiments. Cell proliferation analysis was used to measure the inhibitive effect of triptolide on proliferation of TM4 cells; DCFH-DA (6-carboxy-2',7'-dichlorofluorescein diacetate) probe was used to stain the TM4 cells, the level change of intracellular ROS was discovered through flow cytometry; the TM4 cells were stained by Annexin V-FITC/PI to detect whether triptolide induced apoptosis in the TM4 cells; Protein was extracted from the TM4 cells in control and triptolide group. Western blot was performed to determine the expression of apoptosis marker protein cleaved-PARP and PI3K/Akt signaling pathway-related proteins [p-Akt (Ser473), Akt, p-mTOR (Ser2448), mTOR, p-p70S6K (Thr389), p70S6K].@*RESULTS@#Cell proliferation analysis revealed that triptolide reduced the TM4 cells viability significantly compared with control group in a dosage-dependent manner [10 nmol/L: (73.77±20.95)%, 100 nmol/L: (51.60±10.43)%, 500 nmol/L: (44.34±5.78)%]; The level of intracellular ROS in the TM4 cells was significantly induced in a dosage-dependent manner (P<0.01); triptolide remarkably induced early-stage and late-stage apoptosis in the TM4 cells [control: (3.84±1.50)%, 100 nmol/L: (13.04±2.03)%, 200 nmol/L: (16.24±1.34)%, 400 nmol/L: (18.76±3.45)%]; The expression of cleaved-PARP was significantly upregulated in the TM4 cells after incubation with triptolide (P<0.01); The expression levels of p-Akt/Akt and p-p70S6K/p70s6k were significantly increased compared with control group (P<0.01). No significant change was observed among the expression levels of p-mTOR/mTOR (P>0.05).@*CONCLUSION@#In vitro studies showed that triptolide could effectively suppress the proliferation and induce apoptosis of TM4 sertoli cells. The oxidative stress was upregulated after incubation with triptolide, which may be one of the mechanisms of cytotoxicity in TM4 cells. Treatment of triptolide led to activation of Akt and p70S6K, indicating that the PI3K/Akt signaling pathway may be involved in response to oxidative stress in TM4 cells. The activation of PI3K/Akt signaling pathway was one of the molecular mechanisms involved in triptolide-mediated oxidative stress in TM4 cells. Our study provides insight into alleviating reproductive toxicity of triptolide in clinical and developing male contraceptive.

Zinc and low-dose of cadmium protect sertoli cells against toxic-dose of cadmium: the role of metallothionein

The impact of cadmium [Cd] on male infertility may be related to the interaction with metal-binding proteins known as metallothioneins [Mts]. Trace elements like zinc [Zn] have protective effects on testicular damage induced by Cd. We determined the effect of Zn and low-dose Cd pre-treatment on the expression of Mt1 and Mt2 genes on testicular Sertoli cells. The cultured TM4 mouse sertoli cells were treated with 50 micro M ZnSO4 [Zn pre-treated group; ZnPG], 2 micro M CdCl2 [Cd pre-treated group; CdPG], or distilled water [DW pre-treated group; DWPG]. After 18 hour, all of these groups were exposed to 100 micro M CdCl2 for different periods of time [1, 2, 3, and 6 hours]. There was also a control group for all three groups, which was treated only with distilled water [without Cd or Zn pre-treatment]. Cellular viability, Zn and Cd concentrations and gene expression were assessed by MTT, atomic absorption spectrometry and real time PCR methods, respectively. The expression of Mt1 and Mt2 genes in ZnPG, CdPG, and DWPG was greater than the control group [p=0.02 and p=0.01, respectively]. Cd concentrations in CdPG and DWPG were greater than the control group [p=0.00]. Expression of both genes in ZnPG and CdPG increased after 3 hours of treatment and Cd concentration decreased simultaneously, which was more obvious in ZnPG. Zn and short term low-dose Cd pre-treatment might reduce the adverse effects of Cd by increasing expression of Mts genes in Sertoli cells. The protective effect of Zn was stronger than Cd

Effect of an anti-thyroid drug, 2,8-Dimercapto-6-hydroxy purine on reproduction in male rats

This histomorphological study is designed to evaluate the peripheral action of 2,8-Dimercapto-6-hydroxypurine [an antithyroid drug] on male reproductive system. The drug was administered as i.p. injection for 21 days to investigate its role on morphology of intratesticular cells and plasma testosterone level. Adult male rats [n=12], divided into three groups i.e. control, dimethylsulphoxide [DMSO] and 2,8-Dimercapto-6-hydroxypurine treated groups and treated with saline, DMSO and 2,8-Dimercapto-6-hydroxypurine for 21 consecutive days respectively. Blood samples were collected at day 1, 7, 14 and 21 and analyzed by using EIA systems. All the animals were scarified on 22nd day and testicular tissues were studied by histomorphpological assesment. 2,8-Dimercapto-6-hydroxypurine caused a significant decrease [P<0.0001] in mean testicular cell population, testicular cell diameter and resulted in arrested spermatogenesis. A significant decrease [P<0.0001] was observed in mean Sertoli and Leydig cell population and diameter in treated group. Similarly a significant decrease was observed in plasma testosterone levels at days 1, 7 and 14 [P<0.05] and further decrease by day 21 [P<0.01] of drug treatment. The present study suggests that 2,8-Dimercapto-6-hydroxypurine is a negative modulator of reproductive system as it suppressed the plasma testosterone level and proliferation of different testicular cell types in adult male rats

Propylthiouracil-induced hypothyroidism delays apoptosis during the first wave of spermatogenesis

Mammalian germ cell apoptosis plays a key role in controlling the correct number of germ cells supported by Sertoli cells during the first wave of spermatogenesis in mammalian puberty. However, little is known about hormonal factors that could influence the rate of germ cell apoptosis during puberty or adulthood. In this work we evaluate germ cell apoptosis under hypothyroidism induced by goitrogen propylthiouracil (PTU) during the first wave of spermatogenesis. Neonatally administered PTU promoted a delay in the differentiation of Sertoli cells as evaluated by the expression of clusterin using immunohistochemistry and RT-PCR. Clusterin had different expression levels in control and PTU-treated animals, but under both conditions the highest levels were found in 35-day-old rats. In addition, clusterin displayed a cytoplasmic localization in control testes, but appeared located in the nucleus in PTU-treated animals. The wave of apoptosis (determined by caspase activity and quantification of apoptotic cells) characteristic of the first round of spermatogenesis was delayed by at least 10 days in these animals. The expression levels of proapoptotic genes like BAX or BAD were different between control and PTU-treated rats; although in both groups the highest level was found at the same age (days). Thus our results indicate that the characteristic pubertal apoptotic wave during rat spermatogenesis is delayed in neonatal hypothyroid rats.

Effect of estradiol on expression of cytoskeletal proteins during spermatogenesis in testis of sexually mature rats.

Earlier studies had shown that long term treatment with estradiol arrests spermatogenesis in adult male rats, at a dose of 0.1 mg/kg/day. The present study was therefore undertaken to ascertain the causes underlying the reduction in sperm counts by administering estradiol for a short term, at the dose of 0.1 mg/kg/day. Estradiol valerate was injected at a dose of 0.1 mg/kg/day, for a period of 10 days to one group of adult male rats, which were administered saline for 12 days prior to estradiol injection, and sacrificed after 22 days. The control group was administered saline for 22 days. The sera were analyzed for testosterone and FSH levels. One testis of each male was immersion fixed for histology, and for immunohistochemistry of two testicular cytoskeletal proteins, vimentin and vinculin. The contralateral testes were used for analysis of vimentin and vinculin gene expression by reverse transcriptase polymerase chain reaction (RTPCR) and western blotting. Another group exposed to estradiol for 10 days was injected with bromodeoxyuridine (BrdU), at a dose of 100 mg/kg/day, to ascertain the effect on germ cell proliferation, and sacrificed 12 days later, while estradiol treatment was continued till sacrifice. BrdU, at a dose of 100 mg/kg/day was injected i.p. to a group of control rats treated with saline for 10 days, and sacrificed 12 days later. The testes from both groups were immersion fixed for immunohistochemical detection of BrdU. Histology of estradiol treated testis showed predominance of tubules with round spermatids with accumulation of lipid droplets in Sertoli cell cytoplasm and decreased cell height, whereas controls showed elongating spermatids. BrdU immunolocalization in the testis, irrespective of treatment, indicated its incorporation in deoxyribonucleic acid (DNA) suggesting that estradiol sustained germ cell proliferation. Both vimentin and vinculin could be immunolocalized to the testis. The testicular levels of vimentin and vinculin, quantified after western blotting, were unaffected. The testicular expression of vimentin and vinculin seen by RTPCR was also unaffected. The study suggested that estradiol induced reduction in sperm counts was not due to adverse effects on proliferation. The observed predominance of seminiferous tubules showing round spermatids, accumulation of lipid droplets as compared to controls suggested that reduction in elongated spermatids occurred through reduced spermiation and phagocytosis. The study also suggested that reduction in Sertoli cell height after short-term estradiol treatment was not due to reduced expression of vimentin and vinculin, which could be maintained by estradiol. However, reduction in Sertoli cell height could have been due to suppression of FSH and testosterone, implicated in the polymerization of vimentin and organization of vinculin, two cytoskeletal proteins involved in inter-Sertoli or Sertoli-germ cell junctions. The study suggested that disorganization of Sertoli cell cytoskeleton and reduction in the volume of Sertoli cells could be an important factor for reduced efficiency of spermatogenesis after exposure to estrogenic molecules.

Testicular cellular toxicity of cadmium : transmission electron microscopy examination.

It is clear that environmental heavy metals influence life systems and reproductive system. In the present study histological investigation revealed that cadmium was testicular toxicant in mice. Here we compared the fine-structure of spermatogenesis in two groups of mice (SWR), experimental and control. The experimental group underwent cadmium ingestion at 1 mg/kg daily for 4 weeks. The control group underwent ingestion of distilled water with equal dosages, using the same type of injectors, for 4-weeks. After cadmium exposure period both control and experimental groups were killed and samples of the testes were processed for microscopic examination. Ultra sections were examined and photographed by Transmission Electron Microscope (JEOL- 100SX) at 80KV. Ultrastructure examination revealed, vascular endothelial, interstitial, and sertoli cells damages. Early impairments of germinal cellular differentiation resulted in deformations in all parts of late spermatid. There were dislocation of accrosomal granules, nuclear damage associated with chromatin heterogeneity, detached spermatid from the apical process of sertoli cell, disarrangement of the mitochondria, abnormal oriented tail piece, and abnormal microtubules complex. These ultra morphological abnormalities relate to cell injury and to the resulting physiological abnormality, necrobiosis. Based on the results of this investigation it can be concluded that cadmium ingestion at 1000 microg/kg caused testicular toxicity and abnormalities in early sperm development.

Male reproductive toxic effects of carbendazim: hitherto unreported targets in testis.

Carbendazim (MBC), a widely used fungicide, is toxic to male reproductive mechanisms. Various cellular targets in the testis for MBC action are being understood only recently and still more targets have been conceived. The present study was aimed at finding such newer targets. Male rats were administered through oral route a single dose of carbendazim (400 mg/kg) and the testis was studied adopting routine histological technique. It has been observed that pachytene spermatocytes could also be targets for MBC action in the testis. The study also reports selective loss of step 14 spermatids, asynchrony of the stages in the spermatogenic cycle and development of Sertoli cell fibrosis of the seminiferous tubules of carbendazim-treated rats. From the different kinds of responses seen in the seminiferous tubules in the same testis to MBC, particularly in the Sertoli cell, MBC action in the testis appears dependent on the stage in the spermatogenic cycle at first exposure.

Effect of depot medroxyprogesterone acetate and testosterone ananthate on the testis of albino rats: ultrastructural and biochemical studies.

Male albino rats were treated with depot medroxyprogesterone acetate (1 mg/animal/day) + testosterone ananthate (100 micrograms/100 g body weight/day) for 30 and 60 days. After 30 days of treatment, all the testicular enzymes like beta-glucuronidase, hyaluronidase, sorbitol dehydrogenase, lactate dehydrogenase, acid and alkaline phosphatase, registered non-significant decrease in their values. Fifty percent of the treated animals achieved sterility after 30 days of treatment. After 60 days of treatment the testis showed degenerative changes in Golgi phase and late spermatids. Changes in the Golgi phase spermatids were related with degeneration of the nuclear membrane. Changes in the late phase spermatids included mitochondrial hypertrophy of the midpieces, membrane lysis, absence of cristae and degeneration of annulus leading to detachment of tail. Cytoplasm of luminal area displayed hypertrophied mitochondria devoid of cristae, prominent appearance of Golgi bodies, intense lysosomal activity and ample vacuolation. Tail fragments of degenerated spermatids prevailed in luminal cytoplasm. Except for beta-glucuronidase which registered a significant decrease, levels of all the other testicular enzymes, viz. hyaluronidase, lactate dehydrogenase, sorbitol dehydrogenase, acid phosphatase and alkaline phosphatase were within their control limits. The ultrastructural and biochemical changes are correlated.

Effect of cyproterone acetate on testis of albino rats: ultrastructural and biochemical approach.

The animals were treated with cyproterone acetate (1 mg/100 g body weight) for 60 days after which the testicular tissue was studied at the ultrastructural level to determine the stage at which the effect took place and to study the magnitude of the effect. The testis showed changes in Sertoli cells, Leydig cells, germ cells and in the spermatids. To correlate these changes, important marker enzymes and other biochemical parameters essential for spermatogenesis were studied after 30 days and 60 days of the treatment. They registered a decrease in their levels as compared with the controls.

Efeitos do gossipol sobre a morfofisiologia testicular / Effects of gossypol on testicular morphology and physiology

Os autores analisam as informaçöes disponíveis sobre os efeitos de gossipol na morfologia e fisiologia dos principais componentes testiculares: células de Leydig, células de Sertoli e células de linhagem espermatogênica