Effect of carvedilol on distribution and expression of connexin43

Objective To observe the effect of carvedilol on the expression of Cx43 in rabbits with myocardial infarction and its association with ventricular arrhythmia.Method Thirty-six rabbits were randomly divided into three groups in equal number(n=12),namely,myocardial infarction(MI)group,carvedilol group and sham MI group.Rabbits of carvedilol group were administered with carvedilol 5 mg kg~(-1)·d~(-1)after MI induced,while no carvedilol was administered to the MI group.The following observations were made:(1)Cx43 density of the epicardial border zone measured by quantitative immnuoconfocal laser scanning,and(2)cx43 protein expression analyzed by western blot.Results(1)Under immunoconfocal laser microscope,the relative density of Cx43 was(0.16±0.06)% in the infarction group and was(0.32±0.11)% in the sham MI group [(0.68±0.15)%,both P0.05],but the level of Cx43 in the carvedilol group was significantly higher than that in the myocardial infarction group(P0.05).(2)By western blot analysis,the carvedilol group again had higher Cx43 protein expression than the infarction group [(0.89±0.28)vs(0.67±0.32,P0.05)] as well. Conclusions Carvedilol may increase the expression of Cx43 protein after myocardial infarction,and this may contribute to its anti-arrhythmic effect.