细胞色素C在ATP耗竭诱导的肾小管上皮细胞凋亡中的作用

目的 研究线粒体细胞色素C的释放在ATP耗竭导致的肾小管上皮细胞凋亡中的作用和机制。方法 应用代谢抑制剂暂时性阻断细胞内ATP的生成，诱导细胞凋亡。利用JC-1测定线粒体膜电位的变化。以间接免疫荧光和western印迹检测细胞色素C在细胞内的分布。荧光肽法测定Caspase3的活性。琼脂糖凝胶电泳分析DNA碎解。结果 肾小管上皮细胞内ATP耗竭时，线粒体膜电位显著降低，细胞浆内细胞色素C的含量增多，Caspase3活性增强。细胞内ATP再恢复时，细胞色素C的释放和Caspase3活性继续增加，并出现DNA的碎解。结论 肾小管上皮细胞ATP耗竭时，线粒体细胞色素C的释放在介导Caspase依赖的细胞凋亡通路中发挥重要作用。

Role of cytochrome C in ATP depletion-induced apoptosis in renal tubular epithelial cells

Objective To investigate the role of mitochondria! cytochrome C in ATP depletion-induced apoptosis in renal tubular epithelial cells. Methods To induce apoptosis, cells were transiently exposed to metabolic inhibitor for 60 to 9C min. Mitochondria! membrane potential was determined with JC-1. Cellular distribution of cytochrome C was detected with either immunofluorescence or Western blot. Caspase 3 activity was measured with fluorometric assay. DNA fragmentation was evaluated by agarose gel electrophoresis. Results During ATP depletion in renal tubular epithelial cells, milochondrial membrane potential started to decline and cytochrome C content in cytoplasm arose. Caspase 3 activity appeared after 60 min exposure to metabolic inhibitor and progressively increased to sevenfold to eightfold after 30 min recovery. DNA ladder formation was detected after 90 min of ATP depletion followed by recovery. Conclusion Cytochrome C release from mitochondria in ATP depleted renal tubular epithelial cells plays an essential role in initiating Caspase-dependent apoptosis.