Shimizu S, Eguchi Y, Kamiike W, Akao Y, Kosaka H, Hasegawa J, Matsuda H, Tsujimoto Y
Department of Medical Genetics, Osaka University Medical School, Suita, Japan.
Am J Physiol. 1996 Dec;271(6 Pt 1):G949-58. doi: 10.1152/ajpgi.1996.271.6.G949.
Cell death due to reoxygenation after hypoxia was characterized in primary cultured hepatocytes. Fluorescence and electron microscopic analyses of reoxygenated hepatocytes revealed morphological characteristics of apoptosis, including chromatin condensation, nuclear fragmentation, and formation of apoptotic bodies. Few necrotic hepatocytes, defined by loss of plasma membrane integrity, mitochondrial swelling, and formation of large vacuoles, were observed. Activation of interleukin-1 beta-converting enzyme (ICE)-like and CPP32/Yama-like proteases, which are known to drive apoptosis, was observed during reoxygenation, and addition of their respective inhibitors inhibited the induction of apoptosis, indicating the involvement of ICE family proteases in apoptosis by reoxygenation. Production of oxygen radicals was enhanced by reoxygenation of hypoxic cells, and reoxygenation-induced apoptosis was inhibited by oxygen radical scavengers, suggesting a role for reactive oxygen species as a triggering factor in cell death. Electrophoretic analysis revealed the presence of 50-kb DNA fragments but not oligonucleosomal DNA fragments in reoxygenation-induced apoptotic hepatocytes.
在原代培养的肝细胞中对缺氧后复氧所致的细胞死亡进行了特征描述。对复氧肝细胞的荧光和电子显微镜分析揭示了凋亡的形态学特征，包括染色质浓缩、核碎裂以及凋亡小体的形成。观察到极少的坏死肝细胞，其定义为质膜完整性丧失、线粒体肿胀以及大空泡的形成。在复氧过程中观察到白细胞介素-1β转化酶（ICE）样和CPP32/Yama样蛋白酶的激活，已知这些蛋白酶可驱动凋亡，并且添加它们各自的抑制剂可抑制凋亡的诱导，这表明ICE家族蛋白酶参与了复氧诱导的凋亡。缺氧细胞复氧会增强氧自由基的产生，而复氧诱导的凋亡会被氧自由基清除剂抑制，这表明活性氧作为细胞死亡的触发因素发挥了作用。电泳分析显示，在复氧诱导凋亡的肝细胞中存在50-kb的DNA片段，但不存在寡核小体DNA片段。
