Ghrelin和obestatin对大鼠缺血再灌注心肌的作用及其机制的实验研究

Ghrelin and obestatin is encoded by same gene and derived from same peptide precursor. Evidence is accumulating to indicate that ghrelin and obestatin are related with heart diseases. We will investigate the effects of ghrelin and obestatin on myocardium ischemia/reperfusion injury in vivo and in vitro and explored the possible mechanisms at cellular and molecular level. The langendorff-perfused heart model of ischemia-reperfusion will be used. We will investigate the effects of ghrelin and obestatin on myocardial and clarify the possible molecular mechanism from oxidative stress and the apoptosis initiated by mitochondria pathway. Rat myocardium ischemia/reperfusion injury will be induced by occluding the left main coronary artery. To explore the molecular mechanisms, the activation of NF-κB and its regulated inflammatory mediators expression and apoptotic cardiomyocytes will be examined. We will investigate the effects of ghrelin and obestatin against injury in cultured rat cardiomyocytes and clarify the possible molecular mechanism from oxidative stress, function of mitochondria and cell apoptosis. These observations will provide supporting evidence for the potential therapeutic application of ghrelin and obestatin in patients with cardiac ischemia/reperfusion injury.

Ghrelin和obestatin是同一基因来源的新发现的体液因子，它们与很多心血管疾病及其危险因素密切相关。我们将从整体、器官和细胞三个层次，并从细胞、基因、蛋白等水平多方面探讨ghrelin /obestatin系统对心肌缺血再灌注的作用及其相关的机制。建立离体心脏缺血再灌注损伤模型，观察ghrelin /obestatin系统对心肌的影响，并从氧化应激和线粒体介导的细胞凋亡方面探讨其作用机制。建立大鼠在体心肌缺血再灌注模型，观察ghrelin /obestatin系统对NF-κB信号途径以及细胞凋亡的影响，探讨其心肌保护作用机制。建立体外心肌细胞培养缺氧/复氧模型，观察ghrelin /obestatin系统对心肌细胞的影响，并从氧化应激、线粒体功能以及心肌细胞凋亡方面探讨其机制。从而为心肌缺血再灌注临床有效的治疗提供新的理论基础和治疗靶点。

Ghrelin和obestatin是同一基因来源的新的体液因子，它们与很多心血管疾病及其危险因素密切相关。本研究采用大鼠离体心脏缺血再灌注损伤模型，结果表明在缺血前和再灌注期给予ghrelin或obestatin能明显改善心肌的机械功能，降低冠脉流出液心肌酶的活性，明显减轻了心肌缺血再灌注损伤，其心肌保护作用可能与保护线粒体，增加线粒体活力和降低膜肿胀度有关；建立了大鼠在体心肌缺血再灌注损伤模型，结果表明ghrelin /obestatin系统能明显缩小心肌梗死的面积，其机制可能与下调心肌细胞中细胞因子、炎性介质以及粘附分子有关，如改变TNF-α、IL-6、ICAM-1和iNOSmRNA的表达，降低心肌缺血再灌注时大鼠血清LDH的含量，从而减轻缺血再灌注损伤；建立了大鼠原代心肌细胞缺氧/复氧模型，结果表明ghrelin /obestatin系统能明显抑制细胞的凋亡，其机制可能与增强细胞的抗氧化能力，抑制线粒体途径的细胞凋亡有关。本研究基本完成计划内容，从整体、器官和细胞三个层次，并从细胞、基因、蛋白水平多方面探讨ghrelin /obestatin系统对心肌缺血再灌注的作用及其相关的机制，为心肌缺血再灌注临床有效的治疗提供新的理论基础和治疗靶点。