ABSTRACT
OBJECTIVE@#To investigate the expression of myocardium connexin 43 (Cx43) in late exercise preconditioning (LEP) cardioprotection.@*METHODS@#Eight-week-old adult male Sprague Dawley rats were randomly assigned into four groups (n = 8). Myocardial injury was judged in accordance with serum levels of cTnⅠ and NT-proBNP as well as hematoxylin basicfuchsin picric acid staining of myocardium. Cx43 mRNA was detected by in situ hybridization and qualified by real-time fluorescence quantitative PCR. Cx43 protein was localized by immunohistochemistry and its expression level was determined by western blotting.@*RESULTS@#The LEP obviously attenuated the myocardial ischemia/hypoxia injury caused by exhaustive exercise. There was no significant difference of Cx43 mRNA level between the four groups. Cx43 protein level was decreased significantly in group EE (P < 0.05). However, LEP produced a significant increase in Cx43 protein level (P < 0.05), and the decreased Cx43 protein level in exhaustive exercise was significantly up-regulated by LEP (P < 0.05).@*CONCLUSIONS@#LEP protects rat heart against exhaustive exercise-induced myocardial injury by up-regulating the expression of myocardial Cx43.
ABSTRACT
Objective: To investigate the expression of myocardium connexin 43 (Cx43) in late exercise preconditioning (LEP) cardioprotection. Methods: Eight-week-old adult male Sprague Dawley rats were randomly assigned into four groups (n = 8). Myocardial injury was judged in accordance with serum levels of cTn[U+2160] and NT-proBNP as well as hematoxylin basicfuchsin picric acid staining of myocardium. Cx43 mRNA was detected by in situ hybridization and qualified by real-time fluorescence quantitative PCR. Cx43 protein was localized by immunohistochemistry and its expression level was determined by western blotting. Results: The LEP obviously attenuated the myocardial ischemia/hypoxia injury caused by exhaustive exercise. There was no significant difference of Cx43 mRNA level between the four groups. Cx43 protein level was decreased significantly in group EE (P < 0.05). However, LEP produced a significant increase in Cx43 protein level (P < 0.05), and the decreased Cx43 protein level in exhaustive exercise was significantly up-regulated by LEP (P < 0.05). Conclusions: LEP protects rat heart against exhaustive exercise-induced myocardial injury by up-regulating the expression of myocardial Cx43.