维生素E对大鼠心肌缺血再灌注损伤的影响

Effects of Vitamin E on myocardial ischemic reperfusion injury of rats

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。

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 myocardium and increasing the level of SOD and GSH-PX in serum and myocardium ,the level of Na＋-K＋-ATPase,Ca＋＋-ATPase in myocardial mitochondria .