Abstract:Objective To investigate the effects of bisoprolol on the functions of cardiomyocyte and MAPK/ERK1/2 signaling pathway in rats with chronic heart failure. Methods SD rats were randomly divided into three groups: control group, model group and bisoprolol group (n?=?15). Cardiac function of mice in each group was detected, HE staining was performed on myocardial tissues, and the expression level of related proteins in myocardial tissues was detected. Results The comparison of the indexes of cardiac function in the three groups were statistically significant by analysis of variance (P?0.01). Compared with the control group, LVEDD and LVESD in the model group increased (P?0.05), while LVPWTd, VPWTs and LVEF decreased (P?0.05). Compared with the model group, LVEDD and LVESD in the bisoprolol group decreased (P?0.05), while LVPWTd, LVPWTs and LVEF increased (P?0.05). The comparison of biochemical indexes of chronic heart failure in the three groups was statistically significant by analysis of variance (P?0.05). The levels of NT-proBNP, Mb, cTnI and CK-MB in model group were the highest, followed by bisoprolol group and control group, but the other indexes in model group were the lowest (P?0.05) by pairwise comparison. The comparison of MAPK/ERK signaling pathway-related protein expression in myocardial tissue of the three groups was statistically significant by analysis of variance (P?0.05). Compared with the control group, ERK1/2 and p-MAPK protein levels in the model group increased (P?0.05), while ERK1/2 and p-MAPK protein levels in the bisoprolol group decreased (P?< 0.05). Conclusion Antisterone can protect cardiac myocytes of rats with heart failure by inhibiting the activation of MAPK / ERK1/2 signaling pathway.