大鼠脑缺血预适应对脑线粒体功能的影响

Effect of brain ischemic preconditioning on brain mitochondrial functions during the middle cerebral artery occlusion in rat

观察缺血预适应对大鼠大脑中动脉梗塞的保护作用 ,以及对大鼠脑线粒体功能的影响。观察大鼠双侧颈总动脉缺血预适应后 ,短暂缺血作用对脑梗塞面积、神经症状评分、倾斜板停留时间的影响 ,并测定线粒体复合酶活性、膜肿胀、膜电位、膜流动性的变化。与大脑中动脉梗塞 (MCAO)组比较 ,预适应可以显著降低大脑梗塞面积 (P <0 0 0 1) ;明显改善神经症状评分 ;延长在倾斜板上停留时间 (P <0 0 0 1) ;并可增强线粒体复合酶Ⅰ、Ⅲ、Ⅳ活性 ;线粒体膜肿胀降低 (P <0 0 0 1) ,流动性好于MCAO组 (P <0 0 1) ;膜电位无显著性变化。结果表明 ,缺血预适应对脑有保护作用 ;

It is well known that in the heart, a brief episode of ischemia increases tolerance to a subsequent severe ischemia. In the present study, bilateral carotid arteries occlusion was applied as preconditioning to testify whether this kind of ischemia could preserve the function of mitochondria after the impairment induced by middle cerebral artery occlusion (MCAO) in brain. After the ischemic insult, slope board experiment was performed and stroke indices, brain Infarct area were evaluated. The activities of respiratory chain complex Ⅰ,Ⅱ ,Ⅲ and Ⅳ in mitochondria and mitochondrial swelling、membrane potential and membrane fluidity were tested. Compared with MCAO group, ischemic preconditioning significantly attenuated brain infarct area ( P <0.001); the staying time on slope board was longer than that of MCAO group ( P <0.001), a great difference in stroke indices was also revealed. The activity of enzyme complex Ⅰ,Ⅲ and Ⅳ was enhanced after ischemic preconditioning; mitochondrial swelling was less than that of MCAO group( P <0.001); membrane fluidity was improved as compared with that of MCAO group( P <0.01); No difference was found between MCAO and ischemic preconditioning. These results suggest that ischemic preconditioning can protect brain from ischemic injury and the mitochondrion was protected.