人体肝癌和正常肝脏细胞内硒与氧化应激机制的初步探讨

目的　探讨微量元素硒和氧化应激水平在肝癌发展中的作用。方法　采集了数例肝癌晚期切除样品及其癌旁正常组织 ,测定了正常肝脏组织和癌组织不同细胞器中硒的含量以及超氧化物歧化酶 (SOD)、谷胱甘肽过氧化物酶 (GSH -Px)、硫氧还蛋白还原酶 (TrxR)活性及谷胱甘肽 (GSH)和蛋白总巯基的含量。结果　Se在肝癌溶酶体 (P <0 0 5 )、微粒体 (P <0 0 5 )、细胞质中的含量高于正常肝组织 ,几种抗氧化酶酶的活性和巯基含量均高于正常肝。癌细胞中的Se含量要明显高于相应的癌旁周围正常肝细胞 ,尤其是细胞核、线粒体和细胞质。癌细胞线粒体、细胞质中几种抗氧化酶的活性以及巯基含量均高于相应的癌旁正常肝细胞。结论　癌细胞代谢旺盛 ,摄取更多的营养物质 ,从而造成周围正常细胞营养素的缺乏 ,抗氧化能力的下降 ,其机制还有待进一步研究

Preliminary study on cellular status of selenium and oxidative stress in human hepatocellular carcinoma and normal liver

To investigate the roles of essential trace element selenium and cellular antioxidative systems in human hepatocellular carcinoma, we analyzed cellular distribution of selenium and assayed cytosolic and mitochondrial superoxide dismutase, glutathione peroxidase, thioredoxin reductase, glutathione and total protein thiols in 10 control healthy subjects, 6 cases of hepatocellular carcinoma and 2 cases of nomal liver adjacent to the hepatocellular carcinoma. In hepatoma tissues, the Se contents in lysosome (P<0.05), microsome (P<0.05) and cytosol were higher than in the control liver. In 2 cases, nomal liver adjacent to hepatocellular carcinoma had decreased Se content. In hepatoma tissues, GSH and protein thiols content and activities of SOD, GSH-Px and TrxR were all much higher than in normal liver tissue. These findings suggested the antioxidative defense-related enzymes and antioxidant were largely regulated in hepatoma cells, wheareas the cause is not clear and requires further studies.