胰高血糖素样肽-1对大鼠心肌缺血再灌注/细胞缺氧复氧损伤的保护作用及机制

摘要

目的:观察胰高血糖素样肽-1(GLP-1)对大鼠心肌缺血再灌注/细胞缺氧复氧损伤的作用并探讨其机制.方法:建立大鼠缺血再灌注模型,分别设假手术组(sham)、缺血再灌注组(IR)和IR + GLP-1(0.030 nmol/L、0.16 nmol/L和0.30 nmol/L)组,缺血30 min后再灌注3 h,Evans blue-TTC法检测心肌梗死范围;取左心室游离壁心肌组织,TUNEL法检测心肌细胞凋亡,同时测定心肌组织中氧化-抗氧化物质超氧化物歧化酶(SOD)活性及丙二醛(MDA)含量;培养乳鼠心肌细胞,随机分为正常对照组(control)、单纯缺氧复氧组(HR)、HR + GLP-1(1 μmol/L、5 μmol/L和10 μmol/L)组,电镜下观察心肌细胞形态的变化,流式细胞术检测心肌细胞的凋亡,测定乳酸脱氢酶(LDH)释放、SOD活性、MDA含量、活性氧簇(ROS)水平以及线粒体膜电位(MMP).结果:与IR组相比,IR+GLP-1(0.03 nmol/L、0.16 nmol/L和0.30 nmol/L)组剂量依赖性地减小心肌梗死面积,减轻线粒体超微结构改变及细胞凋亡,增加SOD活性,减少MDA含量(P<0.05 或P<0.01);与HR组相比,HR+GLP-1(1 μmol/L、5 μmol/L和10 μmol/L)组剂量依赖性地逆转HR诱导的细胞损伤,增加SOD活性,减少MDA含量,降低ROS水平,减轻HR诱导的MMP降低(P<0.05或P<0.01).结论:GLP-1可以减轻大鼠心肌缺血再灌注/细胞缺氧复氧损伤;其作用机制可能与增强心肌抗氧化能力及保护线粒体结构和功能有关.%AIM: To invesligale the effects of glucagon - like peplide - 1 ( GLP - 1) on myocardial ischemia - reperfusion ( IR)/hypoxia - reoxygenation (HR) injury in rats. METHODS; Sprague - Dawley rats were randomly divided into 5 groups: sham group, IR group and IR + GLP - 1 ( 0. 03 nmol/L,0.16 nmol/L and 0. 30 nmol/L) groups. IR group and IR + GLP - 1 group were subjecl Lo 30 min of ischemia and 3 h of reperfusion. The myocardial infarct size, the ullraslruclural changes of the myocardial tissues, the apoplosis of the cardiomyocyles, the aclivily of superoxide dismulase (SOD) and the concentration of malondialdehyde (MDA) were delecled. Primarily cullured cardiomyocyles were divided inlo 5 groups at random; conlrol group, HR group and HR + GLP - 1(1 μmol/L, 5 μmol/L and 10 μmol/L) groups. The morphology and apoplosis of the cardiomyocyles were observed. The levels of laclale dehydrogenase (LDH) , MDA,SOD, reaclive oxygen species (ROS) and milochondrial membrane polenlial (MMP) in different groups were delecled. RESULTS : Compared with IR group, the myocardial infarcl size and cardiomyocyle apoplosis were remarkably reduced, milochondrial ullraslruclures were improved, the aclivily of SOD was increased and the concenlralion of MDA was decreased in IR + GLP - 1 (0. 03 nmol/L, 0. 16 nmol/L and 0. 30 nmol/L) groups. Compared wilh HR group, GLP -1(1 μmol/L, 5 μmol/L and 10 μmol/L) preconditioning significantly decreased the myocardial injury, increased SOD aclivily, decreased MDA concenlralion and ROS production, and heightened MMP in a dose - dependent manner. CONCLUSION; GLP - 1 protects cardiomyocyles from IR/HR injury, which may be partially due lo the effecls of anti - oxidative mechanism and the function of milochondrial protection.