Objective To investigate the effect of
astragaloside on myocardial
cathepsin B(CB)mRNA expression, one of the active components
of astragalus membranaceus, in coxsackievirus B_3(CVB_3)inducing murine myocarditis model.Methods One hundred Balb/c mice were randomly divided into 6 groups.Group A < n =10,treated with carboxymethycellulose(CMC) 0.1 mL,intragastric administration (ig) for 1 week> was served as normal control and group B< n =10,treated with 9%
astragaloside 0.1 mL, ig, for 1 week>as treatment control.Eighty infected animals treated with CMC and 1%,3%,9% astragaloside 0.1 mL,ig,for 1 week( n =20,in each group)were served as group C,D,E and F. The mice were killed and their hearts were removed after the 14th day. The expression levels of CB mRNA in the myocardium were examined by RT-PCR.Results The mortality was significantly reduced in 9% astragaloside treated infected animals that was 10%(2/20) vs 45%(9/20)in group C, χ 2=6.14 P <0.05. In uninfected animals, 9% astragaloside did not cause any death. The expression levels of CB mRNA and myocardial histopathologic scores were significantly lower in group F than those in group C. However, the CB expression and myocardial histopathologic scores were not affected by 1% and 3% astragaloside.Conclusions Astragaloside might play a pivotal role in curing the heart injure in Balb/c mice with CVB_3 myocarditis by suppressing excessive expression of myocardial
cathepsin B.