基于内源性保护通路的大蒜素后适应改善心肌缺血/再灌注损伤的分子机制研究

Ischemia/reperfusion (I/R) injury is one of the important factors which influence the effect of reperfusion treatment in the clinical setting. It is the important pathway to relieve I/R injury and reduce the myocardium infarct area by scavenging ROS effectively and promoting the endogenous cardioprotection pathway. It was proved in our previous studies that the infarct area was limited compared with control group by garlicin in swine I/R model. On the basis of the previous study results, further research in Chinese mini-swine I/R injury model will be promoted on the machenism of endogenous myocardial protecting pathway mediated by garlicin postconditioning. Meanwhile swine primary cardiomyocytes will be cultured to discuss the cardioprotective effect of postconditioning. Focusing on mitochondrial ATP-sensitive K+ channels (mitoKATP), reperfusion injury salvage kinase(RISK)pathway and survivor activating factor enhancement (SAFE) pathway, the mechanism and targets of garlicin postconditioning will be discussed and clarified to prevent myocardium I/R injury in molecular and cellar level. Our research will provide a new theoretical support on understanding the pathological mechanism of I/R injury and may contribute a lot in novel therapeutic strategy and theoretical evidence for acute myocardial infarction.

缺血/再灌注损伤是影响急性心肌梗死再灌注治疗预后的重要因素之一。采取有效措施清除氧自由基，激活内源性心肌保护通路，是减轻心肌细胞缺血/再灌注损伤的发生，减少梗死面积的重要途径。本课题组前期研究证实大蒜素能有助于减少猪急性心肌梗死面积，拟在前期研究基础之上,通过猪心肌缺血/再灌注损伤动物模型对大蒜素后适应介导的心肌内源性保护通路进行深入研究。同时以猪原代心肌细胞为切入点，围绕线粒体ATP敏感性钾通道、生存活化因子增强途径(SAFE)、再灌注损伤营救激酶途径(RISK)等，对大蒜素后适应发挥其心肌保护作用的机制及作用靶点进行深入探讨，旨在明确阐述大蒜素后适应防治心肌缺血/再灌注损伤的作用及其机制，为急性心肌梗死患者再灌注治疗及改善患者预后提供全新的干预手段和坚实的理论依据。

缺血/再灌注损伤是影响急性心肌梗死再灌注治疗预后的重要因素之一。采取有效措施清除氧自由基，激活内源性心肌保护通路，是减轻心肌细胞缺血/再灌注损伤的发生，减少梗死面积的重要途径。本课题组通过建立实验猪缺血/再灌注模型，应用压力导管和心电监护系统观察大蒜素对缺血再灌注损伤时血流动力学变化和心律失常发生率的作用，采用心脏声学造影、大体病理染色检测各组心肌梗死区及再灌注区心肌面积的变化。采用Western-blotting法检测各组心肌组织中炎性因子及粘附分子及细胞凋亡相关因子的变化，采用透射电镜检测细胞线粒体的结构变化。此外，培养猪心肌细胞，建立缺氧/再灌注模型，采用TUNEL技术区分正常细胞与凋亡细胞，利用流式细胞仪检测大蒜素对凋亡细胞的影响，分别使用细胞因子IL-6、TNF-α抑制剂和PI3K/AKT、JAK/STAT3抑制剂，阻断两条被研究的细胞信号通路，检测大蒜素抑制细胞凋亡是否与线粒体相关，通过电镜技术观察线粒体结构的变化。研究发现大蒜素可以减少心肌梗死面积，抑制细胞凋亡，减轻细胞内活性氧水平，改善细胞活性。对线粒体检测分析发现，大蒜素可减轻心肌细胞线粒体损伤，减轻缺血再灌注引起的线粒体膜电位下调。进一步研究发现，大蒜素至少部分通过PI3K/AKT和JAK/STAT3途径抑制细胞凋亡、改善细胞活性，而不通过TNF-α和IL-6抑制凋亡。初步阐述大蒜素后适应防治心肌缺血/再灌注损伤的作用及其机制，为急性心肌梗死患者再灌注治疗及改善患者预后提供全新的干预手段和坚实的理论依据。