Effects of Exhaustive Exercise and Exercise Preconditioning on Transmural Repolarization Dispersion and Connexin 43 in Rat Heart
Ma Hong
Tian Pan
Li Junxia
Zhao Feng
Wang Yang
Cui Yingkai
Zhang Gang
Cao Xuebin
Abstract：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.
Keywords：exhaustive exerciseexercise preconditioningtransmural dispersion of repolarization (TDR)connexin 43(Cx43)rats
Publication Date：2018-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：5( 292-296 )