大鼠肝再生早期线粒体介导的caspase-3激活的机制

Mechanism of mitochondria-mediated activation of apoptotic enzyme caspase-3 during early phase of liver regeneration in rats

目的:从线粒体介导的内源性途径分析大鼠肝再生早期肝细胞凋亡执行酶caspase-3激活的机制。方法:雄性SD大鼠35只,分成模型组15只(70%肝切除制作肝再生模型)、假手术组15只和正常对照组5只。模型组和假手术组根据时间分为术后3、6和24 h三个亚组,每个亚组5只。取各组大鼠肝组织,制备肝匀浆液。荧光法测肝组织凋亡酶caspase-3和caspase-9的活性;酶联免疫分析法测谷胱甘肽过氧化酶(GSH-Px)活性;硝酸还原法测NO含量。结果:与假手术组相比,模型组凋亡酶caspase-3和caspase-9的活性在肝再生早期(术后3、6 h组)显著增高(P<0.01);GSH-Px水平显著降低,NO分泌量显著增高(P<0.01)。结论:肝再生早期,肝组织处于氧化应激状态,线粒体介导的内源性途径参与凋亡执行酶的激活。

Objective： To analyze the activation mechanism of hepatic apoptosis-related enzyme caspase-3 during the early phase of liver regeneration in rats from the perspective of mitochondria-mediated endogenous signal pathway. Methods： Thirtyfive male SD rats were randomly divided into 3 groups： model group [70% partial hepatectomy （PH）, n= 15], sham-operated group （n= 15）, and control group （n = 5）. The former 2 groups were further divided into 3 subgroups according to time after operation （3 h,6 h,and 24 h after operation,5 animals in each group）. The animals in all groups were sacrificed and the liver homogenates were prepared. Using the fluorescence method, we determined the activities of hepatic caspase-3 and caspase-9 at 3 different time points after operation. The activity of glutathione peroxidase （GSH-Px） and the content of NO were examined by enzyme immunoassay and nitrate reductase assay,respectively. Results： The activities of hepatic caspase-3 and 9 both increased significantly compared with those of sham-operated group （P〈0.01） at 3 h and 6 h after operation; the level of GSH-Px was significantly decreased and the content of NO was significantly increased compared with those of the sham-operated group （P〈 0.01）. Conclusion： Hepatic tissue is under oxidative stress during the early phase of liver regeneration,and the mitochondria-mediated endogenous signal pathway is involved in the activation of caspase-3.