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

Effects of glucagon-like peptide-1 on myocardial ischemia-reperfusion/hypoxia-reoxygenation injury in rats

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(0.030nmol/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(1μmol/L、5μmol/L和10μmol/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(1μmol/L、5μmol/L和10μmol/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 investigate the effects of glucagon - like peptide - 1 （ GLP - 1 ） on myocardial ischemia - reperfusion （ IR）/hypoxia - reoxygenation （HR） injury in rats. METHODS ： Sprague - Dawley rats were randomly di- vided into 5 groups： sham group, IR group and IR ＋ GLP - I （0.03 nmol/L, 0.16 nmol/L and 0.30 nmol/L） groups. IR group and IR ＋ GLP - 1 group were subject to 30 min of ischemia and 3 h of reperfusion. The myocardial infarct size, the ultrastructural changes of the myocardial tissues, the apoptosis of the cardiomyocytes, the activity of superoxide dismutase （SOD） and the concentration of malandialdehyde （MDA） were detected. Primarily cultured cardiomyocytes were divided into 5 groups at random： control group, HR group and HR ＋ GLP - 1 （ 1μmol/L, 5 μmol/L and 10 μmol/L） groups. The morphology and apeptosis of the cardiomyocytes were observed. The levels of lactate dehydrogenase （ LDH）, MDA, SOD, reactive oxygen species （ROS） and mitochondrial membrane potential （MMP） in different groups were detected. RESULTS ： Compared with IR group, the myocardial infarct size and cardiomyocyte apeptosis were remarkably reduced, mito- chondrial ultrastructures were improved, the activity of SOD was increased and the concentration of MDA was decreased in IR ＋ GLP - 1 （0.03 nmol/L, 0.16 nmol/L and 0.30 nmol/L） groups. Compared with HR group, GLP - 1 （ 1μmol/L, 5 μmol/L and 10μmol/L） preconditioning significantly decreased the myocardial injury, increased SOD activity, decreased MDA concentration and ROS production, and heightened MMP in a dose - dependent manner. CONCLUSION： GLP - 1 protects cardiomyocytes from IR/HR injury, which may be partially due to the effects of anti - oxidative mechanism and the function of mitochondrial protection.