中文摘要：

为探索大豆异黄酮对过氧化氢（H2O2）致肝细胞损伤的保护作用,以H2O2损伤Chang Liver细胞建立肝细胞氧化应激损伤模型,并以10,20和40 mg·L^-1大豆异黄酮进行干预。采用四甲基偶氮唑盐比色（MTT）法检测肝细胞存活率;以微板法检测细胞培养液中乳酸脱氢酶（LDH）、谷丙转氨酶（ALT）、谷草转氨酶（AST）活性和肝细胞超氧化物歧化酶（SOD）活性,以及肝细胞还原型谷胱甘肽（GSH）和丙二醛（MDA）含量;采用蛋白印迹技术检测肝细胞核因子-E2相关因子2（Nrf2）蛋白含量。在10～40 mg·L^-1范围内,大豆异黄酮对Chang Liver细胞不显示细胞毒作用。300μmol·L^-1H2O2刺激后,模型组肝细胞存活率与正常组比较下降,细胞外液中ALT、AST、LDH水平上升,说明Chang Liver细胞损伤显著;而模型组肝细胞中SOD和GSH水平与正常组比较下降,丙二醛水平上升,说明模型组Chang Liver细胞氧化应激增强。大豆异黄酮可剂量依赖性地提高Chang Liver细胞存活率,降低ALT、AST、LDH向细胞外液的释放;降低细胞MDA水平,升高细胞SOD和GSH水平,增高核中Nrf2蛋白水平。研究结果显示大豆异黄酮对H2O2致肝细胞氧化应激损伤具有保护作用。

英文摘要：

The protective effect of soy isoflavones on oxidative damage induced by hydrogen peroxide（ H2O2） in liver cells was investigated. Chang Liver cells were exposed to H2O2 and used as the model of oxidative damage. Then the antagonist effect of soy isoflavones was detected by pretreatment with 10, 20 and 40 mg·L^-1 of soy isoflavones prior to H2O2 challenge. Cell via- bility was evaluated with MTT assay. The activities of LDH, ALT, AST in culture fluid, and levels of superoxide dismutase （SOD）, reduced glutathione （GSH）, and malondialdelyde（MDA） of liver cells were measured by the microplate tecnique. The protein expression of nuclear factor erythroid2-related factor 2 （Nrf2） was determined with the immunoblotting technique. The results showed that 300 μmol· L^-1 H2O2 inhibited cell viabilities, elevated the leakage of LDH, ALT and AST to culture fluid, reduced the levels of SOD and GSH, and increased MDA content in Chang Liver ceils. Soy isoflavones did not exert a toxic effect on Chang Liver cells at the concentrations of 10 -40 mg· L^-1, while H2O2 increased oxidative stress and decreased the cell viability. Compared with the model group, cell viabilities of soy isoflavone group increased in a dose-dependent man- ner. Soy isoflavones also reduced the leakage of LDH, ALT and AST to culture fluid, reduced MDA content, and increased the levels of SOD and GSH. The administration with soy isoflavones up-regulated the protein expression of Nrf2. Taken together, soy isoflavones have the protective effect on cellular oxidative damage induced by H2O2 in liver cells.