Pathways involved in testicular germ cell apoptosis induced by H2O2in vitro
Pathways involved in testicular germ cell apoptosis induced by H2O2in vitro
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DOI：
10.1111/j.1742-4658.2008.06831.x
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发表时间：
2009-02-01
期刊：
影响因子：
5.4
通讯作者：
Nandan, Deoki
中科院分区：
文献类型：
--
作者：
Maheshwari, Ankur;Misro, Man M.;Nandan, Deoki
H2 O2可诱导多种细胞凋亡，但睾丸生殖细胞对H2 O2的敏感性尚不清楚。在本研究中，发现浓度在1-10 μ m范围内的H2 O2在体外诱导睾丸生殖细胞凋亡。用10 μ m H2 O2处理1小时后，观察到凋亡细胞百分比增加10倍。生殖细胞凋亡的诱导与脂质过氧化反应的显著增加（P < 0.01）以及伴随的超氧化物歧化酶和过氧化氢酶活性的降低直接相关。细胞凋亡信号通路的检查显示，在最高浓度的H2 O2暴露下，外源性（Fas、FasL和caspase-8）和内源性（Bid、巴克、Bad、Bax和caspase-9）标记物以及p53的表达增加，同时Bcl-2蛋白的表达沿着降低。发现c-jun N-末端激酶和p38磷酸化形式都被上调。有趣的是，还观察到核转录因子κ B的上调。许多上述蛋白质的各自转录物遵循相同的趋势。据估计，Caspase-3活性也高出30倍。综上所述，上述数据表明，睾丸生殖细胞易于在非常低浓度的H2 O2下发生凋亡，其机制涉及外源性和内源性以及其他调节途径。
H2O2 induces apoptosis in variety of cells; however, the sensitivities of testicular germ cells to H2O2 are not known. In the present study, H2O2, at concentrations in the range 1-10 mu m, was found to induce apoptosis in testicular germ cells in vitro. Following 1 h of treatment with 10 mu m H2O2, a 10-fold rise in the percentage of apoptotic cells was observed. Induction of germ cell apoptosis was directly associated with a significant (P < 0.01) increase in lipid peroxidation and a concomitant decrease in superoxide dismutase and catalase activity. Examination of apoptotic signalling pathways revealed an increased expression of extrinsic (Fas, FasL and caspase-8) and intrinsic (Bid, Bak, Bad, Bax and caspase-9) markers, as well as p53, along with a simultaneous decrease in the Bcl-2 protein at the highest concentration of H2O2 exposure. Both, c-jun N-terminal kinase and p38 phosphorylated forms were found to be up-regulated. Interestingly, up-regulation of the nuclear transcription factor kappa B was also observed. The respective transcripts for many of the above proteins followed an identical trend. Caspase-3 activity was also estimated to be 30-fold higher. Taken together, the above data indicate that testicular germ cells are prone to apoptosis at very low concentrations of H2O2, the mechanism of which involves extrinsic and intrinsic as well other regulatory pathways.