克山病心肌线粒体氧化损伤的实验研究

用克山病区粮喂养豚鼠证明其红细胞、肝等组织及其线粒体、上清中的硒及谷胱甘肽过氧化物酶活性明显降低,心肌线粒体脂质氢过氧化物、荧光色脂等增加、同时膜脂组成异常,内膜界面脂的心磷脂(CL)减少,细胞色素C氧化酶(CCO)活性降低;园二色性(CD)异常,近208nm及222nm区的峰值降低,病区粮加喂青菜的动物,随其线粒体硒及CL水平的增加。CCO活性和CD谱均明显恢复;通过外源性磷脂与纯化CCO的重组复性实验,只有CL可使病区粮组酶活性完全达到正常对照水平。表明心肌线粒体膜结合酶CCO活性的降低是CL含量降低引起酶的二级结构(构象)改变的结果。

Experimental Study on the Oxidative Damage in Myocardial Mitochondria of Keshan Disease Model

The Model test by guinea pigs fed with cereals from Keshan disease (KD) endemic area have been shown, the selenium (Se) content and glutathione peroxidase (GSH-Px) activity in red cell ghosts, homogenate of liver and myocardium and their mitochondria were all decreased significantly.The contents of lipid hydroperoxide and fluorescent chromolipid in myocardial mitochondria were increased, and abnormal viewed in its lipid component,the content of cardiolipin(CL)as a boundary lipid and activity of cytochrome c oxidase (CCO) in mitochondria decreased.At the same time the circular dichroism (CD) in mitochondrial CCO of endemic model showed an abnormal spectra, their peaks in 208nm and 222nm were all lower, in the case of test group supplemented with vegetables, accompanying increase in contents of Se and CL in mitochondria, its enzymatic activity and CD spectra were also restored near to the normal level of control.Through a reconstitution test of purified CCO with exogenous phospholipids, it proved, only in the case of addition with CL, the activity of CCO from endemic model could be restored perfectly, illustrating that the falling of CCO activity in myocardial mitochondria of KD patient and animal model was a result of changing in secondary conformation of enzyme (CCO) provoked by decrease in content of its essential boundary lipid CL.