Angermüller S, Künstle G, Tiegs G
Department of Anatomy and Cell Biology II, University of Heidelberg, Heidelberg, Germany.
J Histochem Cytochem. 1998 Oct;46(10):1175-83. doi: 10.1177/002215549804601009.
Tumor necrosis factor (TNF) induces apoptotic death of hepatocytes in the galactosamine (GalN)-sensitized mouse liver after 5 hr. In our study, the most remarkable sign of the early stage of apoptosis was the focal rupture of the outer mitochondrial membrane. Parts of the inner membrane extended through the gap of the outer membrane, whereas the rest of the inner membrane still formed the cristae. This feature appeared in hepatocytes before chromatin condensation. With the diaminobenzidine technique for localization of cytochrome oxidase activity, the reaction product was detectable by light and electron microscopy. Ten percent of the hepatocytes were apoptotic, with condensed chromatin and high enzyme activity, 37% were pre-apoptotic, without chromatin condensation but high enzyme activity, and 53% had neither condensed chromatin nor a remarkable reaction product of cytochrome oxidase activity. Fas (APO-1, CD95) molecules on the plasma membrane of hepatocytes increased and were represented immunohistochemically in cells without chromatin condensation. DNA strand breaks were also detectable before chromatin aggregation. The results of this study indicate that mitochondria play a pivotal role in pre-apoptotic hepatocytes, together with an increase of the Fas molecule on the plasma membrane and with the occurrence of DNA strand breaks in the nucleus.
肿瘤坏死因子（TNF）在5小时后可诱导半乳糖胺（GalN）致敏的小鼠肝脏中的肝细胞发生凋亡性死亡。在我们的研究中，凋亡早期最显著的标志是线粒体外膜的局灶性破裂。内膜的部分延伸穿过外膜的间隙，而内膜的其余部分仍形成嵴。这一特征在染色质浓缩之前出现在肝细胞中。采用二氨基联苯胺技术定位细胞色素氧化酶活性，通过光学显微镜和电子显微镜均可检测到反应产物。10%的肝细胞发生凋亡，染色质浓缩且酶活性高；37%为凋亡前期，无染色质浓缩但酶活性高；53%既无染色质浓缩也无明显的细胞色素氧化酶活性反应产物。肝细胞质膜上的Fas（APO-1，CD95）分子增加，并在无染色质浓缩的细胞中通过免疫组织化学法显示出来。在染色质聚集之前也可检测到DNA链断裂。本研究结果表明，线粒体在凋亡前期的肝细胞中起关键作用，同时质膜上Fas分子增加以及细胞核中出现DNA链断裂。
