Death receptor response in rodent testis after mono-(2-ethylhexyl) phthalate exposure

Apoptosis of testicular germ cells is critical for the maintenance of functional spermatogenesis. Previously, we have demonstrated that the Fas (Apo-1, CD95) receptor participates in the regulation of germ cell apoptosis, particularly after toxicant-induced Sertoli cell injury. In this study, we show that germ cells from B6.SMNC3H-Fas(gld,gld) (gld) mice that express a dysfunctional form of FasL still undergo significant apoptosis, albeit at a lower incidence than seen in B6 mice, following mono-(2-ethylhexyl) phthalate (MEHP)-induced Sertoli cell injury. In addition, we show the presence of Fas, TRAIL-R1 (Death Receptor-4, DR4), and TRAIL-R2 (DR5) in the testis of C57BL/6 (B6) and gld mice (4 weeks old), and Sprague-Dawley rats (5 weeks old) and their responsiveness after MEHP treatment. More importantly, Western blot analysis of cellular fractions showed an increase in death receptor localization on the membrane fractions taken from Sprague-Dawley rats. Immunohistochemical analysis indicated localization of Fas and DR5 primarily to the spermatocyte subpopulation of germ cells. Examination of downstream receptor-mediated signals (i.e., cleavage of procaspase-8 and NFkappaB activation) revealed an early increase in NFkappaB-DNA binding and an increase in procaspase-8 processing in mutant gld mice. In summary, germ cell-associated death receptors, as well as downstream signaling elements, appear to be responsive to MEHP-induced Sertoli cell injury. Whether this is directly responsible for the increases in germ cell apoptosis after MEHP exposure is yet to be determined. The observed robust and early increase in Fas in wild-type testis and diminished rates of germ cell apoptosis in mutant testis (gld and lpr(cg)) reiterates the importance of the Fas signaling pathway.     

Fas／FasL基因在11酸睾酮诱导恒河猴无精子症或少精子症中的作用

目的：研究凋亡相关基因Fas/FasL在11酸睾酮诱导无精子症或少精子症的作用。方法：TUNEL用于检测睾丸细胞的凋亡信号。免疫组化和Western blot用于对这些凋亡相关基因所表达的蛋白进行定量或定性分析。结果：11酸睾酮处理后,生精细胞的凋亡信号和Fas/FasL蛋白的表达呈现时间依赖性方式增强,至第30天达到最大值。结论：Fas系统可能参与启动和调节11酸睾酮诱导的生精细胞的凋亡。     

Fas- or FasL-deficient mice display an increased sensitivity to nitrobenzene-induced testicular germ cell apoptosis

We have previously reported that the Fas/Apo-1/CD95-mediated apoptosis-inducing signaling system participates in the initiation of toxicant-induced testicular germ cell apoptosis. The contribution of Fas-mediated signaling is especially evident in the initiation of germ cell apoptosis after mono-(2-ethylhexyl)phthalate (MEHP)-induced Sertoli cell injury. In previous work, we demonstrated that the incidence of germ cell apoptosis after MEHP exposure is significantly reduced in B6.SMNC3H-Fas(gld,gld) (gld) mice that express a dysfunctional form of the FasL protein (the associated ligand that activates Fas). This has led to the hypothesis that activation of the Fas-mediated signaling pathway is a common mechanism for the initiation of germ cell apoptosis after toxicant-induced Sertoli cell injury. To test this hypothesis, we evaluated the sensitivity of testicular germ cells of wild-type, gld- and Fas-deficient CBA/KlJms-Tnfrsf6lpr-cg((lpr-cg)) (lpr(cg)) mice to undergo apoptosis after exposure to the Sertoli cell toxicant nitrobenzene (NB). Adult, 8-week-old gld mice treated with a single oral dose of NB (800 mg/kg) were observed to have a higher apoptotic index (AI; 66.1+/-1.3) 24 h after exposure as compared with the wild-type C57BL/6 (C57) mice (50.4+/-1.8). Similarly, 8-week-old lpr(cg) mice treated with NB displayed a higher AI 24 h after exposure (45.1+/-4.6) as compared with the wild-type CBA/KlJms (CBA) mice (32.1+/-3.8). Interestingly, exposure of both peri-pubertal 4-week-old C57 and gld mice showed a similar increase in the incidence of germ cell apoptosis after NB (600 mg/kg) exposure. Taken together, these findings indicate that Fas-mediated signaling is not required for NB-induced germ cell apoptosis and imply that a dysfunctional Fas signaling system sensitizes adult mice to NB-induced germ cell elimination.     

Involvement of Fas/FasL system in apoptotic signaling in testicular germ cells of male Wistar rats injected i.v. with microcystins

Previous studies have shown that gonads were the second target organ of microcystins (MCs), and that MCs exposure exerted obvious toxic effects on male reproductive system of mammals. However, relevant molecular evidences are still lacking. Fas-signaling pathway plays a key role in toxicant-induced germ cell apoptosis. This study was to evaluate the responses of Fas/FasL system related genes and proteins in testes of rats injected intravenously with MCs. Enhanced apoptosis of germ cells in the testes of MCs-treated rats was detected by the terminal deoxynucleotidyl transferase-mediated deoxy-UTP nick end labeling (TUNEL) associated with up-regulation of the Fas/FasL system. Both Fas and FasL protein expression were induced evidently from 1 h post-injection, and this high expression level maintained throughout the experiment. In addition, the activation of caspase-8 and caspase-3 protein was also observed, which were indicators of apoptosis. These results suggested the likely involvement of Fas/FasL system in the MCs-induced germ cell apoptosis. It is also suggested that MCs can cause damage to Sertoli cells directly.     

Elevated serum soluble Fas ligand is a promising marker of testicular toxicity induced by epirubicin in rats

To investigate the role of the Fas/Fas ligand (Fas/FasL) system in testicular toxicity induced by epirubicin (Epi) and to correlate the system with the serum levels of soluble Fas and Fas ligand (sFas/sFasL), epirubicin was intraperitoneally administered to male Sprague–Dawley male rats at doses of 1.2 mg/kg once a week for 10 weeks, and genital organ weights and histopathology were examined. Fas and FasL expression in rat testis were examined by immunohistochemistry. Apoptosis was assessed by TUNEL assay. Expression levels of Fas and FasL were analyzed by RT-PCR and Western blotting. Serum sFas/sFasL levels were determined by ELISA. The results show that the testicular toxicity of Epi involved germ cell apoptosis. Fas and FasL protein expression levels were markedly increased in Epi-treated rat testes, as was expression of sFasL. In particular, increasing serum sFasL levels were positively correlated with elevated expression levels of FasL and sFasL in the testes of Epi-treated rats, revealing serum sFasL to be a promising marker of testicular toxicity after cytotoxic chemotherapy.     

Defining the cellular and molecular mechanisms of toxicant action in the testis

A symposium was held at the 41st annual meeting of the Society of Toxicology with presentations that emphasized novel molecular and cellular pathways that modulate the response to testicular toxicants. The first two presentations described cellular alterations after exposure to the Sertoli cell toxicant, mono-(2-ethylhexyl) phthalate (MEHP). The expression of flamingo1, a G protei coupled receptor family member that may couple cell-cell adhesion to G protein-dependent signaling in Sertoli cells, was rapidly altered after MEHP exposure. Sertoli cell associated flamingo1 immunostaining was redistributed early (within 2 h) after MEHP exposure and disappeared by 12 h, suggesting that flamingo1 is a proximal phthalate target. MEHP was also described to alter the expression and activity of the newly identified death receptors DR4, 5 and 6 in the testis. The differential cellular changes in the levels of DR4, 5 and 6 after phthalate exposure suggested that they may act as surrogates or in concert with the widely described Fas-signaling pathway in the initiation of germ cell apoptosis after MEHP exposure. The next two presentations focused on revealing mechanisms that may explain the persistent post-exposure testicular atrophy that is observed in rodents after a variety of chemical or physical insults (radiation, chemotherapeutics, toxicants) and possible strategies to re-initiate spermatogenesis in the atrophic testis. Hormonal manipulations that lower testosterone and serum FSH levels allow for re-initiation of spermatogonial development. Recent investigation of additional models of persistent atrophy such as mutant mice, the aged Brown Norway rat, EDS-induced Leydig cell deficient rat, and primates, have broadened insight into the mechanisms responsible for persistent atrophy. The last presentation described the use of cDNA arrays in the investigation of cellular elements and mechanisms responsible for disruption of spermatogenesis by the drinking water disinfectant bromochloroacetic acid (BCA). A custom mouse testis cDNA array interrogating 950 genes was used for analysis of testis mRNA. BCA altered the expression of 53 of the 950 genes, including two encoding sperm proteins known to be significant for male fertility, and other genes involved in spermatogenesis, stress response, and cell communication/adhesion. These observations strengthen the hypothesis that BCA disrupts spermatogenesis by altering the process of spermiogenesis.     

Induction of Fas receptor and Fas ligand by nodularin is mediated by NF-κB in HepG2 cells

Nodularin is a natural toxin with multiple features, including inhibitor of protein phosphatases 1 and 2A as well as tumor initiator and promoter. One unique feature of nodularin is that this chemical is a hepatotoxin. It can accumulate into the liver after contact and lead to severe damage to hepatocyte, such as apoptosis. Fas receptor (Fas) and Fas ligand (FasL) system is a critical signaling network triggering apoptosis. In current study, we investigated whether nodularin can induce Fas and FasL expression in HepG2 cell, a well used in vitro model for the study of human hepatocytes. Our data showed nodularin induced Fas and FasL expression, at both mRNA and protein level, in a time- and dose-dependent manner. We also found nodularin induced apoptosis at the concentration and incubation time that Fas and FasL were significantly induced. Neutralizing antibody to FasL reduced nodularin-induced apoptosis. Further studies demonstrated that nodularin promoted nuclear translocation and activation of p65 subunit of NF-κB. By applying siRNA targeting p65, which knocked down p65 in HepG2 cells, we successfully impaired the activation of NF-κB by nodularin. In these p65 knockdown cells, we observed that Fas and FasL expression and apoptosis induced by nodularin were significantly reduced. These findings suggest the induction of Fas and FasL expression and thus cell apoptosis in HepG2 cells by nodularin is mediated through NF-κB pathway.     

Mitochondrial signaling pathway is also involved in bisphenol A induced germ cell apoptosis in testes

Bisphenol A (BPA) is a potential endocrine disruptor and testicular toxicant. An earlier study showed that BPA-induced germ cell apoptosis through the Fas/FasL apoptotic pathway. In the present study, we aimed to investigate whether the mitochondrial pathway is also involved in the process of BPA-mediated germ cell apoptosis in testes. Male mice were administered with BPA (160 or 480 mg/kg) by gavage daily from postnatal day 35 (PND35) to PND49. Germ cell apoptosis in testes was determined by terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick-end labeling (TUNEL). As expected, the number of TUNEL+ germ cells per tubule and the percentage of tubules with TUNEL+ germ cells were significantly increased in testes of mice treated with BPA during puberty. TUNEL+ germ cells were observed mainly in stages VII–VIII seminiferous tubules in testes. An increase in the level of Fas and FasL was observed in testes of mice exposed to BPA during puberty. In addition, pubertal BPA exposure evoked the activation of caspase-8 and caspase-3 in testes. Interestingly, pubertal BPA exposure also caused the translocation of cytochrome c from mitochondria into cytosol. In addition, pubertal BPA exposure upregulated the level of Bax and active caspase-9 in testes. Taken together, these results suggest that pubertal BPA exposure induces germ cell apoptosis in testes through not only the Fas/FasL signaling pathway but also the mitochondrial apoptotic pathway.     

The acute effects of mono(2-ethylhexyl)phthalate (MEHP) on testes of prepubertal Wistar rats

A single oral dose of 400 mg/kg body weight of mono(2-ethylhexyl)phthalate (MEHP), the testis toxic metabolite of di(2-ethylhexyl)phthalate, was given to 28-day-old male Wistar rats and the testis toxic effects were investigated 3,6, and 12 h after exposure. Detachment and sloughing of germ cells were observed, and in the Sertoli cells the cytoplasmatic intermediate filament vimentin collapsed. In the immunohistochemical investigation the androgen receptor distribution was unchanged between the control group and treated groups. The expression of the testosterone-repressed-prostatic-message-2 gene in rat testis increased after 3 h, but returned to control levels after 6 and 12 h. Caspase-3 activity increased 3 and 12 h after MEHP exposure. This increase could not be correlated to an increase in DNA fragmentation or increase in apoptotic numbers of germ cells. In conclusion, the effect of MEHP in testis is apparently not involving the androgen receptor. Vimentin localisation in the Sertoli cells, and increased levels of caspase-3 activity appear to be sensitive and early markers of MEHP testis toxicity.     

低剂量毒死蜱重复染毒诱发雄性大鼠生殖毒性及其机制

目的探讨毒死蜱(CPF)低剂量重复染毒对雄性大鼠生殖功能的影响及其可能作用机制。方法健康雄性Wistar大鼠ig给予CPF 1,5和10 mg.kg-1,每日1次。连续染毒12周后取大鼠附睾和睾丸称重计算脏器系数,进行组织病理学、精子数量以及活力及畸形率等检查,测定睾丸碱性磷酸酶(AKP)、酸性磷酸酶(ACP)、γ-谷氨酰转肽酶(γ-GT)和乳酸脱氢酶(LDH)的活性;TUNEL法检测细胞凋亡,免疫组化及Western印迹法检测胱天蛋白酶和Fas,FasL蛋白的表达。结果与正常对照组相比,CPF染毒大鼠睾丸脏器系数显著升高,精子数及精子活力降低,精子畸形率显著升高(P<0.05),睾丸AKP和γ-GT活性抑制明显。组织病理检查显示,睾丸曲细精管疏松和生精细胞减少。CPF染毒组生精细胞凋亡增加(P<0.05)。Fas/FasL蛋白表达量升高。结论 CPF低剂量重复染毒能够诱导雄性大鼠生殖毒性,其作用机制可能与激活Fas/FasL受体途径而引起睾丸生精细胞凋亡有关。     

莪术油诱导K-562细胞凋亡分子机制的实验研究

目的探讨莪术油(OCW)诱导慢性粒细胞白血病(CML)细胞株K-562凋亡及可能的分子机制。方法以不同浓度OCW(0,2.5,5,10和20 mg/mL)处理K-562细胞24 h后,光镜下观察形态学改变;CCK-8法检测细胞增殖抑制率;Hoechest33258荧光染色及FITC-AnnexinⅤ/PI双染法检测细胞凋亡率;半定量RT-PCR及Western blot方法检测bcr/abl、bcl-2、p53、Fas/FasL表达的变化。结果OCW明显抑制K-562细胞增殖,诱导细胞凋亡,与浓度呈正相关;各组药物干预后Fas/FasL基因在mRNA和蛋白水平呈浓度依赖性上调,而bcr/abl、bcl-2、p53基因表达无明显变化。结论不同浓度OCW能有效诱导K-562细胞凋亡,其作用可能通过Fas/FasL途径而实现的,与bcr/abl、bcl-2、p53基因无明显相关。     

Mono(2‐ethylhexyl) phthalate induces apoptosis in p53‐silenced L02 cells via activation of both mitochondrial and death receptor pathways

Mono(2‐ethylhexyl) phthalate (MEHP) is one of the main metabolites of di(2‐ethylhexyl) phthalate. The evidence shows that DEHP may exert its toxic effects primarily via MEHP, which is 10‐fold more potent than its parent compound in toxicity in vitro. MEHP‐induced apoptosis is mediated by either p53‐dependent or ‐independent pathway. However, the detailed mechanism of its toxicity remains unclear. In this study, immortalized normal human liver cell line L02 was chosen, as an in vitro model of nonmalignant liver, to elucidate the role of p53 in MEHP‐induced apoptosis. The cells were treated with MEHP (6.25, 12.50, 25.00, 50.00, and 100.00 μM) for 24 and 36 h, then small interfering RNA (siRNA) was used to specifically silence p53 gene of L02 cells. The results indicated that MEHP caused oxidative DNA damage and apoptosis in L02 cells were associated with the p53 signaling pathway. Further study found that MEHP (50.00 and 100.00 μM) induced apoptosis in p53‐silenced L02 cells, along with the up‐regulations of Fas and FasL proteins as well as increased the Bax/Bcl‐2 ratio and Caspase 3, 8, and 9 activities. Additionally, both FasL inhibitor (AF‐016) and Caspase inhibitor N‐benzyloxycarbonyl‐Val‐Ala‐Asp‐ fluoromethylketone (Z‐VAD‐FMK) could prevent the cell apoptosis induced by MEHP. The findings suggested that MEHP‐induced apoptosis in L02 cells involving a Caspases‐mediated mitochondrial signaling pathway and/or death receptor pathway. p53 was not absolutely necessary for MEHP‐induced L02 cell apoptosis. © 2014 Wiley Periodicals, Inc. Environ Toxicol 30: 1178–1191, 2015.     

BPA-induced apoptosis of rat Sertoli cells through Fas/FasL and JNKs/p38 MAPK pathways

Bisphenol-A was examined for its effects on cultured Sertoli cells established from 18 to 22-day-old rat testes. Results indicated that exposure to BPA (0, 30, 50 and 70 μM) decreased the cell viability in a concentration-dependent manner and induced cell apoptosis. Apoptosis-caused cell death was observed in cells exposed to 50 and 70 μM BPA. The mRNA expressions of Fas, FasL and caspase-3 were all elevated, and the protein expressions of FasL and cleaved caspase-3 were also increased. In addition, levels of phosphorylation of JNKs/p38 MAPK were also increased and then activated JNKs/p38 MAPK up regulated target gene expressions, such as c-jun and CHOP. Translocation of NF-κB into nuclei indicated the activation of NF-κB after treatment with BPA. Taken together, observed results suggest that BPA induces apoptosis of Sertoli cells by the activation of JNKs/p38 MPAK and translocation of NF-κB, and Fas/FasL system plays a critical role in the initiation of apoptosis.     

Studies on the characteristics and mechanisms of testicular toxicity induced by Hydroxyurea

Abstract

Objective: Apoptosis plays a dominant role in both spontaneous spermatogenesis and germ cell death. This study was aimed to investigate the functions of related genes in testicular germ cell death induced by Hydroxyurea (HU).

Method: Wild-type (WT) and FasL transgenic (TG) DBA/C57BL mice were intraperitoneal injected with 400?mg/kg HU. Twelve hours later, testes were collected. Histomorphology of testis was observed by staining with Periodic Acid Schiff (PAS). Apoptosis was assessed by TUNEL assay. mRNA and protein levels of related genes were evaluated by quantitative RT-PCR and Western blot, respectively.

Results: The 2?×?2 factorial design comparative experiments between the WT and TG mice showed that the TG mice exhibited a higher basal apoptotic index. The basal mRNA levels of Fas and FasL and protein levels of Fas, FasL, Caspase-3, Caspase-8 and Caspase-9 in the TG mice were also higher than that in the WT mice. Twelve hours after injection of HU, the testicular tubules exhibited no significantly morphological changes but apoptosis index remarkably increased in both the WT and TG mice, with the latter having the higher amplitude. Although, HU up-regulated the mRNA of apoptosis-related genes, such as Fas and FasL, in both the TG and WT mice, the increased amplitude was more obvious in the TG mice. By Western blot analysis, apoptosis-related proteins Fas, FasL Caspase-3, Caspase-8 and Caspase-9 were significantly increased in both the WT and TG mice, with the TG mice exhibiting a greater up-regulation.

Conclusion: Germ cell apoptosis induced by the HU treatment may be related to the FasL-mediated signal transduction pathway.     

Fas ligand: a potential target for therapeutic immune modulation in transplantation and inflammatory diseases

Fas ligand (FasL) triggers apoptosis of cells expressing its cognate receptor, Fas (CD95/APO-1). FasL precludes inflammatory reactions from immune privileged sites by inducing Fas-mediated apoptosis of infiltrating pro-inflammatory cells. The ability of FasL to impair immune responses is showing therapeutic promise as a possible means of protecting tissue transplants from immunological rejection. However, FasL is becoming an enigmatic molecule, exhibiting pro-inflammatory activity independently of its ability to mediate immune privilege. FasL can recruit and activate neutrophils in some situations. FasL appears to contribute to destruction of Fas-sensitive end-organ cells during inflammation. Prevention of Fas-mediated end-organ apoptosis and enhancement of Fas-mediated apoptosis of inflammatory cells are emerging as potential anti-inflammatory therapeutic goals.     

迷迭香酸抗过氧化氢诱导血管平滑肌细胞凋亡作用的研究

目的探讨迷迭香酸对过氧化氢(H2O2)诱导血管平滑肌细胞凋亡的保护作用及其机制。方法流式细胞术检测细胞凋亡率;吖啶橙(acridine orange,AO)染色观察细胞形态学变化;MTT法检测细胞活性;Western blot检测细胞中Bcl-2、Bax、Fas和FasL蛋白的表达。结果经500μmol·L-1H2O2处理24h后,细胞凋亡率为34.9%±2.55%,出现核固缩、核碎裂等典型的凋亡形态学改变,所以随后实验选择500μmol·L-1H2O2为诱导血管平滑肌细胞凋亡的最佳浓度。①500μmol·L-1的H2O2处理血管平滑肌细胞24h能引起细胞活性明显降低;细胞凋亡率明显增加,达35.7%±1.33%;细胞中Bcl-2蛋白表达降低,Bax蛋白表达升高,Bcl-2/Bax蛋白比值减少,Fas和FasL蛋白表达升高。②用迷迭香酸(10、20、40μmol·L-1)预处理细胞30min,可以增加细胞活性;降低细胞凋亡率,呈浓度依赖性;细胞中Bcl-2/Bax蛋白比值升高,Fas和FasL蛋白表达降低。结论迷迭香酸能拮抗H2O2诱导血管平滑肌细胞凋亡;其作用机制可能与升高细胞中Bcl-2/Bax蛋白比值,减少Fas、FasL蛋白表达有关。     

The pharmacological mechanism underlying the apoptosis of human hepatic stellate cells LX-2 induced by NF-κB inhibitor PDTC

In the present study, we aimed to confirm whether NF-κB inhibitor pyrrolidine dithiocarbamate (PDTC) could induce apoptosis of human hepatic stellate cells (HSCs) LX-2 and explore the potential pharmacological mechanism underlying these effects. In this study, LX-2 cells were cultured in vitro, and the experiment was divided into two groups, including the control and PDTC groups. The viability of LX-2 cells was measured by CCK8 assay after the cells were exposed to PDTC. The anti-apoptotic effect of PDTC was detected by AO/EB double assay staining kit. Additionally, the activities of NF-κB, Fas/FasL, apoptosis-related proteins, as well as the cellular localization of AIF, were determined by Western blotting analysis and immunofluorescence staining respectively. After PDTC treatment for 12 and 24 h, AO/EB dual staining showed typical apoptotic changes, such as cell volume reduction, cell shrinkage, nuclear fragmentation, and so on. PDTC at 60 μmol/L significantly increased the proliferation inhibition rate and decreased the secretion of collagen I, collagen III, and α-SMA in LX-2 cells. The Western blotting analysis and RT-PCR showed no significant difference in the expression of AIF between the control group and PDTC group, and the expressions of Fas and FasL were not observed in all groups (P > 0.05). Further results showed that PDTC could promote the displacement of AIF from mitochondria to the nucleus, activate the apoptotic signaling in the cell nucleus, and possibly participate in the apoptosis process of LX-2 cells. In conclusion, the pharmacological mechanism of PDTC against hepatic fibrosis might be to promote the displacement of AIF from mitochondria to the nucleus, then activate the apoptotic signaling in the cell nucleus, and finally induce the apoptosis of LX-2 cells. Meanwhile, these results also revealed that the Fas/FasL-mediated apoptosis pathway was not involved in the PDTC-induced apoptosis process of LX-2 cells.     

Lindane induces testicular apoptosis in adult Wistar rats through the involvement of Fas–FasL and mitochondria-dependent pathways

Lindane, an organochlorine pesticide, is known to impair testicular functions and fertility. To elucidate the mechanism(s) underpinning the gonadal effects of lindane, we sought to investigate the levels of apoptosis-related proteins, namely cytochrome c, caspase-3 and-9, Fas and FasL in the testis of adult rats. Furthermore, the study aims to delineate whether nuclear factor kappa B (NF-κB) is involved in meditating the testicular effects of lindane. Animals were administered with a single dose of lindane (5 mg/kg body weight) and sacrificed at specific post-treatment intervals (0, 3, 6, 12, 24 and 72 h). Significant elevations in the levels of cytosolic cytochrome c with a parallel increase in pro-caspase-9 were observed as early as 6 h following exposure. Time-dependent elevations in the levels of Fas, FasL and caspase-3 were observed. Immunofluorescence studies revealed increased colocalization of Fas and caspase-3 in peritubular germ cells. FasL levels were increased in Sertoli and peritubular germ cells. The cytoplasmic levels of NF-κB p65 decreased from 3 h following exposure with a maximal decline at 12 and 24 h. Changes in the localization of NF-κB were observed with maximal nuclear translocation in germ cells at 12 and 24 h. Terminal deoxynucleotidyl transferase-mediated dUTP nickend-labeling (TUNEL) assay revealed a time-dependent increase in the number of apoptotic cells. Taken together, the data illustrate induction of testicular apoptosis in adult rats following exposure to a single dose of lindane. Early activation of NF-κB in contrast to late increase in Fas expression suggests a pro-apoptotic role of NF-κB in testicular response to lindane.     

诊断超声照射后人早孕绒毛细胞Fasm RNA FasL mRNA表达的改变

目的　探讨诊断超声与人早孕绒毛Fas/FasLmRNA表达的关系。方法　对拟进行人工流产的 2 4例早孕 (4 5～ 6 0d)妇女随机分为 4组 :Ⅰ组 (对照组 )、Ⅱ组 (10min组 )、Ⅲ组 (2 0min组 )和Ⅳ组 (30min组 )。应用HP 85 0 0彩色多普勒超声诊断仪 ,对孕囊进行不同时间的持续照射 ,照射后 2 4h取材。用原位杂交技术检测上述各组绒毛滋养层细胞Fas/FasLmRNA表达情况。结果　超声照射后 10min组绒毛滋养层细胞Fas/FasLmRNA表达率与对照组差异无显著性 (P >0 0 5 ) ,2 0min组和 30min组滋养层细胞表达率明显增加 ,显著大于对照组和10min组 (P <0 0 0 1)。结论　诊断超声持续照射早孕孕囊组织 >10min可引起绒毛滋养层细胞Fas/FasLmRNA表达率增加 ,从而诱导滋养层细胞凋亡增加