不同力竭运动后大鼠心脏传导系统结蛋白mRNA和蛋白表达的变化及其在运动性心律失常发生中的作用

目的:探讨大鼠力竭运动后不同时相心脏窦房结、房室结和浦肯野氏纤维细胞骨架因子结蛋白在基因和蛋白水平的表达特点,为阐明运动性心律失常发生机制提供实验依据。方法:100只健康成年雄性SD大鼠随机分为一次力竭组(4组)、2周反复力竭组(4组)及其相应的安静对照组,每组10只。分别于力竭运动后即刻、4、12及24小时,先进行心电图(ECG)检测,随即应用激光显微切割技术定位并收集窦房结、房室结和浦肯野氏纤维细胞团,采用免疫荧光组化及实时荧光定量PCR检测分析结蛋白mRNA和蛋白表达。结果:不同力竭运动后,部分大鼠发生心律失常,本研究建立的运动性心律失常模型成功。一次和反复力竭运动后,大鼠窦房结结蛋白mRNA和蛋白表达水平规律基本一致,12小时窦房结结蛋白mRNA和蛋白表达显著低于对照组(P<0.05)。一次和反复力竭运动后,房室结结蛋白mRNA和蛋白表达规律基本一致,运动后24小时下降较明显(P<0.05)。反复力竭运动后4小时浦肯野氏纤维结蛋白mRNA和蛋白表达均显著低于一次力竭后(P<0.05)。结论:不同力竭运动后心脏传导系统各部位细胞骨架支撑因子结蛋白在mRNA和蛋白水平存在低表达,且反复力竭后心脏传导系统改变更明显,提示力竭运动可致心脏传导系统骨架因子结蛋白受损,可能是发生运动性心律失常的病理基础。

The Expression of Desmin in Cardiac Conduction System after Exhaustive Exercise

Objective To investigate the gene and protein expression characters of cytoskeleton factor desmin in cardiac sinus node(SAN),atrioventricular node(AVN),and Purkinje fibers at different time-phrases after exhaustive exercise,in order to provide experimental evidence for clarifying the mechanism of exercise-induced arrhythmia.Methods One hundred healthy adult male SD rats were divided into 4 acute exhaustive swimming groups,4 2-week repeated exhaustive swimming groups,and corresponding control groups(each group contained 10 rats).Rats were sacrificed 0,4,12,and 24 hours after exhaustive swimming,then the SAN,AVN and Purkinje’s fibers were spotted and collected with the approach of Laser Micro dissection(LMD) and immune fluorescent histochemistry at the different time-phrases.The mRNA and protein expression of desmine in the SAN,AVN and Purkinje’s fiber cells were analyzed by real-time fluorescent quantitative PCR,immunochemistry,and image analysis.Results As compared to the control group,the mRNA and protein of desmin expression in SAN decreased significantly 12 hours after two exhaustive exercises(P < 0.05).As compared to the acute exhaustive exercise group,the mRNA and protein of desmin expression in AVN decreased significantly 24 hours after two exhaustive exercises,and in Purkinje’s fiber decreased significantly 4 hours after exercise in repeated exhaustive exercise group(P < 0.05).Conclusion After exhaustive exercise,the abnormal mRNA and desmin protein expression demonstrated the damage of cytoskeleton,and damage of cytoskeleton could be the pathological basis of exercise-induced arrhythmia.