Effect of carvedilol on cardiac function and sympathetic nerve remodeling after myocardial infarction in rats

Objective To explore the effects of carvedilol on heart function and cardiac sympathetic nerve remodeling after myocardial infarction(MI)in rats.Methods Eighty male Wistar rats were randomly assigned into three groups:MI group(n=30),carvedilol group(n=30)and sham operation(SO)group(n=20).The model of MI was made by ligation of the left anterior descending artery.The carvedilol group were treated with carvedilol 5 mg/kg twice a day after the operation while the MI group and SO group were treated with saline.Eight weeks later,the heart rate(HR),left ventricular end-diastolic pressure(LVEDP),left ventricular systolic pressure(LVSP)and the maximum rise and fall rate of left ventricular pressure(±dp/dt)were measured by catheter examination and the expression of growth associated protein 43(GAP43)and tyrosinehydroxylase(TH)at the peri-infarct zone were examined by western blot and RT-PCR analysis.Results Eight weeks after the operation,both HR and LVEDP in the carvedilol group were markedly decreased(P0.05),whereas the LVSP and ±dp/dt were significantly increased(P0.05)compared with the MI group.Furthermore,carvedilol reduced both GAP43 and TH protein production significantly and decreased GAP43 and TH mRNA expression after MI(P0.05).Conclusions carvedilol may ameliorate cardiac function and inhibit sympathetic nerve sprouting at the peri-infarct zone after MI in rats.