有氧运动调节副交感神经及其受体改善心梗大鼠心脏功能机制探讨

The Mechanism of Aerobic Exercise Regulates Parasympathetic Nerve and Its Receptor to Improve Cardiac Function in Myocardial Infarction Rats

目的:探讨有氧运动对心梗大鼠副交感神经M_(2)和α7受体的表达及其对心脏功能调控的影响。方法:选取3月龄雄性SD大鼠36只,随机分成3组:假手术组(n=12,Sham),心梗手术组(n=12,MI),心梗+有氧运动组(n=12,ME)。Sham组大鼠常规饲养,MI组结扎左冠状动脉前降支建立心肌梗死模型,ME组采用跑台训练方式建立有氧运动模型。Powerlab多导生理记录仪测试大鼠血流动力学;伊文思蓝和TTC染色法观察心肌组织梗死面积;H.E.、Masson染色方法观察组织形态学和心肌胶原容积;免疫组化SABC法和WesternBlot测定副交感神经M_(2)和α7受体、eNOS和TNF-α表达;透射电镜观察左心室心肌梗死边缘区超微结构。结果:与假手术组相比,心肌梗死导致心脏功能紊乱,梗死边缘区毛细血管,闰盘和线粒体结构紊乱,下调副交感神经α7受体及eNOS的表达,增加M_(2)受体和TNF-α表达。与心肌梗死组比较,有氧运动干预改善心脏功能,削弱梗死边缘区毛细血管,闰盘和线粒体损伤,增加副交感神经α7受体及eNOS的表达,降低M_(2)受体和TNF-α表达。结论:有氧运动改善心梗大鼠心脏功能可能与有氧运动改善梗死边缘区组织结构,增加副交感神经α7受体的表达,上调eNOS,降低M_(2)受体和TNF-α的表达密切相关。

Objective:To investigate the effects of aerobic exercise on the expression of parasympathetic M_(2) andα7 receptors in cardiac infarction rats and their effects on cardiac function regulation.Methods:36 male SD rats of three months old were randomly divided into three groups:Sham operation group(n=12,Sham),myocardial infarction group(n=12,MI),myocardial infarction+aerobic exercise group(n=12,ME).Sham group was routinely reared,MI group was ligated left anterior descending coronary artery to establish the model of myocardial infarction,the ME group used the treadmill training method to establish the aerobic exercise model.Hemodynamics was measured by Powerlab multi-channel physiological recorder;myocardial infarction area was observed by Evans blue and TTC staining;histomorphology and myocardial collagen volume were observed by H.E.and Masson staining.The expressions of parasympathetic M_(2) andα7 receptors,eNOS and TNF-αwere detected by immunohistochemical SABC method and Western Blot.The ultrastructure of left ventricular myocardial infarction marginal region was observed by transmission electron microscopy.Results:Compared with the Sham operation group,myocardial infarction caused cardiac dysfunction,capillary,disc and mitochondrial structure disorder in the infarct border area,down-regulation of parasympatheticα7 receptor and eNOS expression,and increased M_(2) receptor and TNF-αexpression.Compared with the myocardial infarction group,aerobic exercise intervention improved cardiac function,weakened capillaries,sacral disc and mitochondrial damage in the infarct border zone,increased the expression of parasympatheticα7 receptor and eNOS,and decreased M_(2) receptor and TNF-αexpression.Conclusions:The improvement of cardiac function in myocardial infarction rats by aerobic exercise may be closely related to aerobic exercise in improving the tissue structure of infarct marginal area,increasing the expression ofα7 receptor of parasympathetic nerve,and increasing the expression of eNOS,and decreasing the expression of M_(2) receptor and TNF-α.