OBJECTIVETo investigate the effects of nitric oxide on mitochondrial permeability and cytochrome C (cyt C) of human hepatocellular carcinoma cell lines.

METHODSNO-mediated apoptosis in human hepatocellular carcinoma cell lines SMMC-7721 and HepG2 was investigated by flow cytometry. The growth and proliferation of human hepatocellular carcinoma cell lines SMMC-7721 and HepG2 were evaluted by MTT assay. Mitochondrial transmembrane potential was analyzed by flow cytometry with double staining of Rh123 and PI, and cytoplasmid cyt C was measured by Western blot. The cells were preincubate with cyclosporin A or GSH synthesis blocker BSO to explore their effect on the results of the above experiments.

RESULTSNO donor sodium nitroprusside (SNP) induced apoptosis in human hepatocellular carcinoma cell lines SMMC-7721 and HepG2 and resulted in the decrease of the mitochondrial transmembrane potential and the increase of the amount of cytoplasmid cyt C in time-dependent manner. Cyclosporin A (CsA) specific inhibitor of the mitochondrial permeability transition pore could partially prevent the decrease of delta psi m and the release of cyt C. In contrast, GSH synthesis blocker BSO promoted the decrease of delta psi m and the release of cyt C.

CONCLUSIONSNO may induce apoptosis in human hepatocellular carcinoma cell lines SMMC-7721 and HepG2 by decreasing delta psi m, opening the mitochondrial permeability transition pore, and releasing the cyt C.