细胞色素c在年龄相关性白内障晶状体上皮细胞凋亡中的作用

Function of cytochrome c in human lens epithelial cells apoptosis of age-related cataract

目的观察年龄相关性白内障晶状体上皮细胞细胞色素c表达情况,探讨其与晶状体上皮细胞凋亡的关系。方法取手术中取下的年龄相关性白内障患者的晶状体前囊膜,采用免疫组织化学染色法(SP)检测晶状体上皮细胞细胞色素c表达情况,TUNEL法检测晶状体上皮细胞凋亡情况,并分析与细胞色素c表达的关系。透射电镜观察分析晶状体上皮细胞超微结构。结果正常人晶状体上皮细胞可见细胞色素c均匀胞浆低表达,年龄相关性白内障组在细胞色素c胞浆低表达细胞中,可见散在分布的胞浆高表达细胞。TUNEL阳性细胞仅存在于白内障组。细胞色素c表达与凋亡指数成正相关(P<0·01)。电镜下可见染色质边集、凋亡小体和线粒体肿胀等特征。结论晶状体上皮细胞凋亡可能参与年龄相关性白内障的形成,线粒体细胞色素c凋亡途径可能在白内障的发生发展中起重要作用。

Objective To investigate the expression of cytochrome c in human lens epithelial cells of age-related cataract and study the relationship betwcen cytochrome c and apoptosis.Methods The expression of cytochrome c was detected by using immunohistochemical staining in 35 cases of age-related cataract. Transmission electron microscopy was used to observe the apoptotic morphology and the change of mitochondrion in lens epithelial cells, TDT mediated biotin-dUTP nick-end labeling （TUNEL） was also carried out to detect apoptosis. Results High positive immunolabeling for cytochrome c was found in huaman lens epithelial cells of age-related cataract, while in normal human lens epithelial cells only very low positive immunolabeling was found. TUNEL positive labeling cells only located in age-related cataract. There was a highly significant and positive correlation between the expression of cytochrome c and apoptotic indices（ P 〈 0.01 ）. Chromatin margination, apoptotic bodies and swelling of mitochondrion were found in cataract by electron microscopy.Conclusion Lens epithelial cells apoptosis exists in age-related cataract. Cytochrome c may induce apoptosis and play an important role in the formation of cataract.