深低温停循环后大鼠海马线粒体通透性转换孔开闭情况研究

目的通过对深低温停循环大鼠海马线粒体通透性转换孔(MPTP)开闭情况的研究,从亚细胞水平探讨深低温脑保护的机制。方法取成年SD大鼠33只,3只作为供血动物,剩余30只随机分为深低温停循环组(n=10)、常温停循环组(n=10)、正常对照组(n=10)。采用闭胸式体外插管法建立大鼠体外循环模型。其后采用断头取脑法迅速取出大鼠双侧海马组织,提取线粒体后应用蛋白印记法测量线粒体内细胞色素C(CytC)研究MPTP的开闭情况。结果常温停循环组的MPTP较正常对照组、深低温停循环组的开放明显增加(P<0.05);正常对照组的MPTP开放较深低温停循环组的开放少(P<0.05)。结论缺血缺氧可导致MPTP开放;深低温可抑制MPTP开放,保证了细胞的正常代谢活动从而起到脑保护的作用。

A study on the opening and closing situations of mitochondrial permeability transition pore in rat hippocampus after deep hypothermic circulatory arrest

Objective To investigate the protective effects of deep hypothermia on brain at subcellular level by studying the opening and closing situations of mitochondrial permeability transition pore(MPTP)in rat hippocampus after deep hypothermic circulatory arrest.Methods Thirty-three adult Sprague-Dawley(SD)rats were taken.Three of them were used as the blood-supply animals and the other 30 rats were randomly divided into three groups:deep hypothermic circulatory arrest group(n=10),normal temperature circulatory arrest group(n=10)and normal control group(n=10).The cardiopulmonary bypass(CPB)rat model was established using closed-chest external intubation.Decapitation was performed on the rats and their bilateral hippocampal tissues were quickly removed from the brains to extract mitochondria,and then cytochrome C(CytC)in mitochondria was measured by Western blot to investigate the opening and closing situations of MPTP.Results The opening degree of MPTP in the normal temperature circulatory arrest group was significantly greater than that in the normal control group and the deep hypothermic circulatory arrest group(P<0.05).The opening degree of MPTP in the normal control group was significantly less than that in the deep hypothermic circulatory arrest group(P<0.05).Conclusion Ischemia and hypoxia can lead to the opening of MPTP.Deep hypothermia can inhibit the opening of MPTP,which ensures the normal metabolic activity of cells and thus plays a role in brain protection.