Astragaloside IV reduces cardiomyocyte apoptosis in a murine model of coxsackievirus B3-induced viral myocarditis

Apoptosis plays a crucial role in regulating cardiomyopathy and injuries of coxsackievirus B3 (CVB3)-induced viral myocarditis (VM). It has been reported that Astragaloside IV (AST-IV) from Astragalus membranaceus could inhibit apoptosis under a variety of pathological conditions in vivo or in vitro. However, the functional roles of AST-IV in CVB3-induced VM still remain unknown. Here, we found that AST-IV significantly enhanced survival for CVB3-induced mice. AST-IV protected the mice against CVB3-induced virus myocarditis characterized by the increased body weight, decreased serum level of creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH), supressed expression of Ifn-γ, Il-6 in heart, enhanced systolic and diastolic function of left ventricle. At the pathological level, AST-IV ameliorated the mice against CVB3-induced myocardial damage and myocardial fibrosis. In vitro, the results from flow cytometry showed that AST-IV significantly suppressed CVB3-induced cardiomyocytes apoptosis, which also were verified in vivo. Moreover, an increased expression of pro-apoptotic genes including FAS, FASL, cleaved caspase-8 and cleaved caspase-3 was found in CVB3-induced cardiomyocytes, while those was inhibited in cardiomyocytes treated with AST-IV. Taken together, the data suggest that AST-IV protected against CVB3-induced myocardial damage and fibrosis, which may partly attribute to supress activation of FAS/FASL signaling pathway.