Objective To explore the effects of β receptors inhibitors on the expression of calcineurin (CaN) and cardiomyocyte apoptosis induced by Ischemia-reperfusion (hypoxia-reoxygenation) and Isoproterenol.

Methods To observe the damage of the cardiomyocyte including myocardial apoptosis and the mRNA levels of CaN, a langendorff perfused model induced by ischemia-reperfusion and isoproterenol (Iso), and neonatal rat cardiomyocytes was cultured after AdCnAα infection. The myocardial apoptosis was judged by TUNEL and DNA ladder, in which flow cytometry was used and the mRNA levels of CaN was investigated by RT-PCR.

Results Pretreatment of carvedilol decreased the mRNA level of CaN and the rates of myocardial apoptosis in the rats myocardial damage model (p<0.05). Atenolol, has trivial effect on the CaN and apoptosis (p > 0.05) in isolated rat heart models. In cultured neonatal rat cardiomyocytes, both carvedilol and atenolol decreased apoptotic rates of cardiomyocytes compared with the control group (p<0.05), the CaN mRNA levels, however, had no significant difference between two groups (p > 0.05).

Conclusions Carvedilol, α1 β receptors inhibitor, might medulate the cardiomyocyte apoptosis by adjusting the mRNA level of CaN; the effect of atenolol, β receptors inhibitor, on the myoccardial apoptosis and the mRNA level of CaN needs to be further studies.