力竭运动和运动预适应对大鼠心脏跨室壁复极离散度和缝隙连接蛋白43影响的研究

摘要

目的 探讨力竭运动(EE)和运动预适应(EP)对大鼠心脏跨室壁复极离散度(TDR)、缝隙连接蛋白43(connexin 43,Cx43)的影响.方法 雄性SD大鼠80只随机分为4组:安静对照(CC)组、运动预适应(EP)组、力竭运动(EE)组、运动预适应+力竭运动(EP+EE)组.记录各组大鼠室性心律失常发生率、T波峰末间期(Tp-e)值、QT间期(QTC)值.光镜和电镜下观察组织病理学改变.运用免疫荧光染色法、免疫印迹法检测各组大鼠心肌总Cx43(Total-Cx43)及磷酸化Cx43 (P-Cx43)分布及量的改变.结果 EE组大鼠心律失常发生率为35%,EP+EE组则降为10%,有显著差异(P<0.05).EE组大鼠Tp-e、QTC分别为(42.4±1.9)ms、(31.9±1.3)ms,EP+EE组降为(36.5 ±1.8)ms、(26.7±1.0)ms,也均有明显差异(P<0.05).EP组、EE组、EP+EE组大鼠心肌Total-Cx43、P-Cx43表达量均减少,但EP+EE组较EE组的Total-Cx43含量却明显升高(P均<0.05).Pearson相关分析,Total-Cx43、P-Cx43均与Tp-e、QTC呈负相关,有显著差异(P<0.05).结论 力竭运动易引发室性心律失常,可能与心肌重构,心肌TDR增加,Total-Cx43、P-Cx43表达量降低有关,而EP则对其有显著保护作用.%Objective To investigate the effects of Exhaustion Exercise (EE) and exercise preconditioning (EP) on transmural dispersion of repolarization (TDR) and connexin 43 (Cx43) in rat heart. Methods Eighty adult male Sprague-Dawley (SD) rats were randomly divided into 4 groups: control (CC) group, exercise preconditioning (EP) group, exhaustion exercise (EE) group, exercise preconditioning+exhaustion exercise(EP+EE)group. The incidence of ventricular arrhythmias, T peak-Tend interval (Tp-e) and QT interphase (QTC) values of each group rats were recorded. The histopathological changes of myocardium were observed by optical microscopy and electron microscope. Using the immunofluorescence staining method and western blotting technology to detect the distribution of Total Cx43 (Total-Cx43) and phosphorylated Cx43 (P-Cx43) and the changes of their quantity. Results The incidence of cardiac arrhythmia in the EE group was 35%, and the incidence of EP+EE group was reduced to 10%, and there was statistically significant difference (P<0.05). There were significant differences between EE group and EP+EE group with respect to Tp-e (42.4±1.9 ms vs. 36.5±1ms) and QTC (31.9±1.3 ms vs. 26.7±1.0 ms, P<0.05). The expression levels of Total-Cx43 and P-Cx43 in EP group, EE group and EP+EE group were all decreased. However, the level of Total-Cx43 in EP+EE group was significantly higher than that of EE group. Total-Cx43 and P-Cx43 were negatively correlated with Tp-e and QTC (P<0.05). Conclusion Exhaustive exercise can lead to ventricular arrhythmia, which may be related to myocardial remodeling, increased TDR of myocardium, decreased expression of Total-Cx43 and P-Cx43, while EP has a significant protective effect on it.