Abstract:Objective: To explore the molecular mechanism of Qiangxin Fumai granule(QFG,an effective Chinese composite drug) in preventing and treating sick sinus syndrome(SSS).Method: Rabbit model of sinoatrial ischemia/reperfusion was established by occluding and loosening the root of right coronary artery.Effect of QFG on cell apoptosis was observed by TUNEL method,and its effect on apoptotic related gene Bax,Bcl-2 and Fas-L gene protein expression was observed by immunohistochemical method.Average light density values of the expression of Bax,Bcl-2 and Fas-L of SAN cells was determined by Imagepro Plus image analysis system.Result: Sinoatrial injury induced by ischemia/reperfusion could cause evident sinoatrial cell apoptosis,enhance Fas-L gene protein expression and obviously enhance Bax gene protein expression,reduce Bcl-2/Bax ratio.QFG could significantly down-regulate Fas-L and Bax gene protein expression,up-regulate Bcl-2/Bax ratio,significantly inhibit and block the sinoatrial cell apoptosis.Conclusion: To inhibit and block the event of cell apoptosis through regulating Bax,Bcl-2 and Fas-L gene protein expression in sinoatrial node after ischemia/reperfusion might be one of the mechanisms of QFG in preventing and treating sinoatrial ischemia/reperfusion injury of SSS.