Objective:To determine the effect of berberine(Ber) on norepinephrine(NE)-induced apoptosis in neonatal rat cardiomyocytes.Methods:The cultured neonatal rat cardiomyocytes were treated with NE in the presence or absence of Ber.The activity of lactate dehydrogenase(LDH) in the culture medium was examined,and apoptosis of cardiomyocytes was assessed by Hoechst 33258,isothiocyanate(FITC)- conjugated annexin-V,and propidine iodide(PI) staining.In addition,the activities of caspases-2 and-3 were measured by a fluorescent assay kit.The level of secreted tumor necrosis factorα(TNF-α) and production of intracellular reactive oxygen species(ROS) were also determined.Results:NE at a concentration of 50μmol/L induced an obvious increase in the activity of LDH in the culture medium(P<0.05),which was inhibited by coincubation with 0.5,1.0,or 2.0μmol/L Ber(P<0.05).Ber also significantly attenuated NE- induced apoptosis in a dose-dependent manner(P<0.01).Moreover,Ber at a dose of 2μmol/L markedly decreased the ROS and TNF-αproductions(P<0.05) and inhibited the activation of caspases-2 and -3 in cardiomyocytes exposed to NE(P<0.05).Conclusion:The present study suggested that Ber could reduce NE-induced apoptosis in neonatal rat cardiomyocytes through inhibiting the ROS-TNF-α-caspase signaling pathway. Objective:To determine the effect of berberine(Ber) on norepinephrine(NE)-induced apoptosis in neonatal rat cardiomyocytes.Methods:The cultured neonatal rat cardiomyocytes would be treated with NE in the presence or without of Ber.The activity of lactate dehydrogenase(LDH ) In the culture medium was examined, and apoptosis of cardiomyocytes was assessed by Hoechst 33258,isothiocyanate(FITC)-conjugated annexin-V,and propidine iodide(PI) staining.In addition,the activities of caspases-2 and-3 were measured By a fluorescent assay kit.The level of secreted tumor necrosis factorα(TNF-α) and production of intracellular reactive oxygen species(ROS) were also determined.Results:NE at a concentration of 50μmol/L induced an apparent increase in the activity of LDH in the culture medium (P<0.05), which was inhibited by coincubation with 0.5,1.0, or 2.0 μmol/L Ber (P<0.05). Ber also significantly attenuated NE-induced apoptosis in a dose-dependent manner (P< 0.01). Moreover, Ber at a dose of 2μmol/L markedl y decreased the ROS and TNF-αproductions (P<0.05) and inhibited the activation of caspases-2 and -3 in cardiomyocytes exposed to NE (P<0.05). Conclusion: The present study suggested that Ber could reduce NE-induced apoptosis in Neonatal rat cardiomyocytes through inhibiting the ROS-TNF-α-caspase signaling pathway.