Objective To investigate the effect and mechanism of Astragalus injection on acute murine myocarditis caused by coxsackievirus
B3. Methods Acute viral myocarditis was induced in 24 BALB/c mice by injection of coxsackievirus B3m(CVB3m) intraperitoneally. Half of the mice were administered Astragalus injection(10 g/kg every day). Heart and blood samples were obtained from all mice on the 8th day of CVB3m infection for hispathological study, detection of
myocardial perforin and CVB3m
expression by reverse transcription-polymerase chain reaction(RT-PCR). Results (1) Astragalus-treated mice showed a significant reduction in myocardial lesion as compared with that in untreated mice. (2) Myocardial perforin expression by semi-quantitative RT-PCR in Astragalus-treated mice was much lower than that in controls(1.10±0.07 vs 1.31±0.12, P<0.01). (3) Myocardial CVB3m expression shown by semi-quantitative RT-PCR in Astragalus-treated mice was much lower than that in controls(1.07±0.04 and 1.18±0.02, P<0.01. (4) Myocardial perforin expression level showed significant positive correlation with the changes of myocardial CVB3m expression(r=0.68, P<0.01). Conclusion Perforin-mediated cytotoxicity may play an important role in the development of viral myocarditis. Astragalus has therapeutic effects on viral myocarditis. The mechanism may be explained by anti-viral efficacy, improving of circulation and lightening of myocardial injure.