[Effect of Astragalus membranaceus on electrical activities of coxsackie B-2 virus-infected rat myocardial cells in culture].

Beating Myocardial cell cultures of neonatal rats were prepared in vitro and infected with coxsackie B-2 virus. The cells were evaluated in the post-infected period for changes in beating percentage and cytopathic effect (CPE), alterations in the electrical activities by standard microelectrode techniques, and the protective effect of Astragalus membranaceus (AM) on coxsackie B-2 virus-infected neonatal rat myocardial cell cultures was observed. The beating percentage began to decrease in the infected group at 24 hr and only 27.9 +/- 18.6% was beating at 96 hr after virus challenge, premature beats, tachycardia and fibrillation occurred commonly during the experiment. Meanwhile the CPE appeared rapidly from 1+-3+ at the same interval. Resting potential, action potential amplitude, duration and rate of uptake were shown a significant decrease through 24-96 hr (P less than 0.01). In contrast, the beating and electrical activities were nearly normal and less CPE was shown in myocardial cells treated with AM 1 hr after virus challenge through 24-96 hr (P less than 0.05). The results suggest that AM may be valuable in prophylaxis and treatment of acute coxsackie B-2 virus caused myocarditis.