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胰岛素对缺血/再灌注冠状动脉的保护作用及其机制研究
Coronary Vasculoprotective Effect of Insulin in Myocardial Ischemia-reperfusion and Its Mechanism of Action
【作者】 马恒;
【导师】 高峰;
【作者基本信息】 第四军医大学 , 生理学, 2006, 博士
【摘要】 研究背景 近年来,缺血性心脏病(IHD)已成为威胁国人健康的“第一杀手”。随着冠状动脉内溶栓及冠脉搭桥等内外科治疗手段的广泛应用,继之出现的再灌注损伤日益受到心脏病学家的高度重视。来自动物实验和临床观察的证据表明,缺血/再灌注损伤会引起冠状动脉功能障碍而加重心肌细胞的损伤;在此过程中冠状动脉内皮细胞凋亡是引起缺血心肌损伤的始动因素。因此,应用各种药物和基因治疗手段保护冠脉功能,抑制和预防冠脉内皮细胞凋亡已引起众多学者的关注。我们以往研究发现胰岛素通过激活细胞PI3K-Akt-eNOS发挥心肌保护作用。然而,胰岛素对缺血/再灌注(I/R)冠脉系统有何影响;尤其是对I/R冠脉血管内皮细胞是否具有直接的保护作用及其机制尚不明确。 一氧化氮(NO)直接参与心血管正常功能的维持。越来越多的证据表明,NO可以对半胱氨酸巯基进行亚硝基化修饰(s-nitrosylation)。目前认为,这种普遍存在的翻译后调节机制与蛋白磷酸化作用相仿,可以影响许多生物过程,包括导致细胞凋亡的多种信号途径。近期研究表明,绝大多数凋亡蛋白caspases,包括caspase-3前体或其激活物,均可被亚硝基化修饰,而且其功能受到抑制。该结果强烈提示:NO通过凋
【Abstract】 BackgroundGrowing evidence from both animal experiments and clinical observations indicates that endothelial dysfunction contributes significantly to subsequent functional and cellular injury through a variety of pathological pathways in myocardial ischemia/reperfusion (MI/R). Considerable evidence exists that coronary artery endothelial apoptosis plays a critical role in myocardial reperfusion injury. Therefore, treatment that reduces coronary endothelial apoptosis may be a novel approach that can reduce ultimate cardiomyocyte death after ischemia and reperfusion. Although our previous work have demonstrated that PI3K-Akt-eNOS pathway is required for insulin’s cardiomyocyte protective effects. Whether insulin may exert a coronary artery endothelial protective effect via Akt-mediated eNOS activation pathway remains unknown.Nitric Oxide (NO) plays an important role in the protection against the onset and progression of cardiovascular disease. Numerous experimental results have demonstrated that low concentrations of NO produced from
【Key words】 Myocardial ischemia/reperfusion; Insulin; Nitrc Oxide; Apoptosis; Nitrosylation;