细胞色素P450 2E1在大鼠急性肝损伤中的表达及其意义

目的研究细胞色素P4502E1在大鼠急性肝损伤中的表达变化及其意义。方法随机将Wista大鼠分成正常对照组和急性肝损伤组，采用四氯化碳制备急性肝损伤模型，并按染毒时间分为3、6、12、24、36和48h6个亚组，每组5只大鼠。采用western blot方法测定染毒后不同时间点肝组织细胞色素P4502E1蛋白的表达变化；测定大鼠血清ALT、AST水平和肝组织MDA浓度、SOD活性的变化以及采用电子自旋共振（ESR）技术测定大鼠肝组织自由基（ROS）浓度变化，HE染色观察肝组织病理形态学改变；结果四氯化碳可明显导致大鼠肝脏损伤，表现为：血清ALT、AST水平显著升高，肝组织MDA浓度和ROS含量显著增加。SOD活性明显下降，和正常对照组相比，差异均十分显著（P〈0．01）；western blot结果显示：细胞色素P4502E1在正常大鼠肝组织中有表达，染毒3h后表达增强，12h达到高峰，明显高于正常对照组（P〈0．05），其表达趋势与ROS浓度变化相一致。结论细胞色素P4502E1蛋白在大鼠急性肝损伤时表达显著增强，提示其在中毒性肝损伤的发病中可能具重要的病理生理意义，并与四氯化碳诱导的氧化应激反应密切相关。

Expression of hepatic cytochrome P450 2E1 in rats with acute liver damage caused by CCl4

Objective To investigate the dynamic expression of hepatic cytochrome P450 2E1 in rat model of acute liver injury induced by CCl_4.Methods Male Wista rats were randomly allocated to establish acute liver damage models by carbon tetrachloride administration intraperitoneally(i.p). Serum aspartate aminotransferase(ALT),alanine aminotransferase(AST) and hepatic MDA concentration and SOD activities were analyzed at different time point following CCl_4 injection. Reactive oxygen species(ROS) production in liver tissue was measured by electron spin resonance(ESR) spectroscopy. Dynamic expression of cytochrome P450 2E1 protein in the liver of CCl_4-treated rats was determined by western blot method. Additionally,histopathological changes were also investigated.Results Administration of carbon tetrachloride to rats caused a marked hepatic damage,characterized by significant elevation of serum ALT,AST levels and liver MDA content,and a remarkable reduction in liver SOD activity when compared with the control group. ESR results indicated that ROS production was much higher in the CCl_4-treated group than that in the control group. CYP450 2E1 protein can be detected in the liver of control rats. A marked elevation of CYP450 2E1 protein could be observed in a time-dependent manner following CCl_4 injection and the significant elevation lasted from 6 hr to 48hr in contrast to control group.Conclusion It seemed that CYP450 2E1 plays a pivotal role in the development of lipid peroxidation and acute liver damage caused by CCl_4.