Astragalus polysaccharide attenuates overexercise-induce myocardial injury via activating AMPK signaling pathway to suppress inflammation and oxidative stress

Excessive exercise leads to myocardial injury or even sudden exercise death. For the vast sports population, appropriate physiological state is a necessary condition for exercise. The present study aims to investigate the cardioprotective effects and potent mechanism of astragalus polysaccharide (APS) treatment against the exerciseinduced myocardial injury via in vitro cell-based assay and in vivo model rat. Efficacies of APS incubation on the inflammatory response and oxidative stress induced by LPS were both explored in H9c2 cells by using CCK-8 and western blotting method, respectively. Normal SD rats were randomly divided into saline-treated overexercise rat group, and APS-treated overexercise rat groups with three doses. Then long-term swimming training load cycle (8 week) were performed on these rats. Finally, the changes on body weight, myocardial morphological and injury indicators, as well as the inflammation-related proteins in overexercise-induced model rats were all assessed. Three concentrations of APS all significantly increased cell viability, and decreased the apoptosis of cardiomyocytes in LPS-treated H9c2 cells. Moreover, chronic treatment of APS at all three doses also could obviously decreased myocardial injury-related indicators. Furthermore, the histopathologic examination exhibited that the APS successfully attenuated the changes of myocardial tissues, reduced the lipid accumulation and the protein levels of IL-1 beta, TNF-alpha and NF-kappa B. Furthermore, the APS could activate the AMPK signaling pathway, enhance the autophagy and suppress the production of ROS. On conclusions, APS exerted the protective efficacies on overexercise-induced myocardial injury by activating the AMPK signaling pathway to increase autophagy and suppress the inflammation response, oxidative stress, apoptosis of myocardial cells.