维生素E对大鼠心肌缺血再灌注损伤的影响

目的观察大鼠心肌缺血再灌注（MIR）时ICAM-1和自由基代谢的变化及维生素E对其的影响,探讨大鼠MIR损伤的可能机制。方法大鼠30只,分为假手术对照组（sham）、MIR组和维生素E＋MIR组,免疫组织化学法检测心肌ICAM-1蛋白表达。检测血清、心肌组织SOD、MDA和GSH-PX及心肌线粒体Na＋-K＋-ATP酶、Mg＋＋-ATP酶、Ca＋＋-ATP酶活性等自由基代谢指标。结果与sham组相比,MIR组心肌线粒体Na＋-K＋-ATP酶、Mg＋＋-ATP酶、Ca＋＋-ATP酶活性明显下降;用维生素E4周后心肌线粒体Na＋-K＋-ATP酶、Ca＋＋-ATP酶活性明显升高。与sham组相比,MIR组血清、心肌MDA明显升高,血清、心肌SOD和GSH-PX明显降低;用维生素E4周后心肌MDA低于MIR组,血清、心肌SOD和GSH-PX水平高于MIR组。与sham组相比,MIR组心肌ICAM-1蛋白质表达明显升高;用维生素E后心肌ICAM-1蛋白质表达低于MIR组。结论MIR时有大量ICAM-1蛋白表达,与心肌损伤关系密切。维生素E可通过减少ICAM-1蛋白表达水平,起心肌保护作用。在MIR时自由基产生增多,维生素E能加速自由基的清除,增强机体的抗氧化能力,从而保护心肌组织免受氧化损伤。

Effects of Vitamin E on myocardial ischemic reperfusion injury of rats

Objective To observe the effects of Vitamin E on the changes of the intercellular adhesion molecule-1 （ICAM-1）and free radicals in ischemic-reperfused myocardium,and to explore the possible pathogenesis of myocardial ischemic-reperfusion injure. Methods Thirty SD rats were divided into three groups with each group 10 rats （ sham group,MIR group and Vitamin E group）. The ICAM-1 protein expressions were examined with immunohistochemical method. The contents of malonaldehyde（MDA） in serum and myocardial tissues were detected. The activities of superoxide dismutase（SOD） and glutathione peroxidase（GSH-PX） in serum and myocardial tissues were measured. The activities of Na＋-K＋-ATPase、Mg＋＋-ATPase、Ca＋＋-ATPase in myocardial mitochondria were examined. Results Compared with sham group ,the activities of Na＋-K＋-ATPase,Mg＋＋-ATPase,Ca＋＋-ATPase in myocardial mitochondriawere decreased significantly in MIR group.Compared with MIR group ,the activities of Na＋-K＋-ATPase,Ca＋＋-ATPase in myocardial cytochrome were increased significantly in Vitamin E group. Compared with sham group ,the value of MDA in serum and myocardium were increased significantly ,the levels of SOD and GSH-PX in serum and myocardium were decreased significantly in MIR group. Compared with MIR group ,the levels of MDA in myocardium were decreased significantly ,the activities of SOD and GSH-PX in serum and myocardium were increased significantly in Vitamin E group. Compared with sham groups,the level of ICAM-1 in myocardium were increased significantly in MIR group. Compared with MIR groups,the level of ICAM-1 in myocardium were decreased significantly in Vitamin E group. Conclusions Vitamin E could relieve myocardial ischemic reperfusion injure induced by MIR,and this action was mediated by reduction of expression of ICAM-1 protein. Vitamin E play essential roles in protective effects on myocardial ischemia and reperfusion injury by scavenging hydroxyl free radicals,decreasing the level of MDA in serum and