[Mechanism of the protective effects of berbamine on ischemia-reperfusion injury in isolated rat heart].

Isolated perfused rat heart model was used to observe the protective effects of berbamine on myocardial ischemia/reperfusion injury. The hearts were remarkably injured by 40 min global ischemia followed by 20 min reperfusion. Berbamine could significantly improve heart function, prevent ventricular fibrillation, reduce CK release, preserve Na, K-ATPase activity, and reduce Na+ gain and K+ loss during ischemia and Ca2+ overload during reperfusion. With the use of low temperature ESR technique, we found that, in hearts subjected to 40 min ischemia and 15 sec reperfusion, oxygen-centered free radical signals became much more intense. In the presence of berbamine, these signals decreased. The results showed that berbamine could alleviate myocardial ischemia/reperfusion injury. This effect might be due to (1) preserved myocardial Na, K-ATPase activity and inhibition of sodium overload at the end of ischemia, which might further lead to attenuation of reperfusion-induced calcium overload, and (2) reduction of oxygen free radical generation during reperfusion.