全肠外营养诱导线粒体应激介导的肝细胞凋亡的研究

目的探讨全肠外营养诱导新生乳猪线粒体应激介导的肝细胞凋亡的作用机制。方法以肠内营养乳猪作为对照，建立全肠外营养新生乳猪实验动物模型，喂养7d后获取肝脏组织，分离原代肝细胞，部分肝组织应用琼脂糖凝胶电泳检测肝细胞DNA凋亡条带，通过凋亡蛋白活性测定、免疫组织化学、Western blot印迹法等检测全肠外营养诱导肝细胞发生凋亡的蛋白表达。结果全肠外营养组乳猪肝细胞活率为（49±21）％，明显低于肠内营养组的（88±14）％（P〈0．05）。全肠外营养乳猪肝组织DNA电泳呈现典型梯形凋亡条带，细胞凋亡ELISA检测发现细胞凋亡定量高达对照组的2．6倍，半胱天冬氨酸蛋白酶（caspase）-3活性也明显升高，与肠内营养相比增高9．9倍，但ATP酶活性下降了24％。Westernblot显示全肠外营养组肝组织中相关凋亡蛋白酶PARP、caspase-9和-7蛋白酶原被活化，Bcl-2蛋白表达量下调，Bax蛋白量表达上调；同时线粒体内细胞色素C释放至胞浆内，使胞浆内细胞色素C表达水平升高。免疫组织化学也显示全肠外营养组Bax表达上调。结论全肠外营养可以损伤肝组织，并通过线粒体应激信号传导通路诱导肝细胞凋亡。

The study of total parenteral nutrition induced hepatocyte apoptosis mediated by mitochondrial stress pathway

Objective To investigate total parenteral nutrition(TPN)-induced apoptosis of hepatocytes mediated by mitochondrial pathway with neonatal piglets as an animal model.Methods Neonatal piglets were sacrificed following 7 days on TPN,while control animals received enteral nutrition(EN).Following removal of small liver segments for morphologic and molecular analysis,piglet hepatocytes(PH) were isolated by perfusion with collagenase and subjected to functional and metabolic studies.DNA fragmentation,cell death de...