[Effects of Chinese herbal medicines Shengmai injection and Xuesaitong injection on ventricular fibrillation threshold and connexin 43 expression in rats with myocardial infarction].

OBJECTIVE

To explore the effects of Shengmai injection and Xuesaitong injection, compound Chinese herbal medicines for replenishing qi and activating blood, on ventricular fibrillation threshold, heart structure and connexin 43 (Cx43) expression in rats with myocardial infarction (MI).

METHODS

One hundred male SD rats were randomly divided into sham operation group, model group, Yiqi Huoxue (YQHX) group (Shengmai injection plus Xuesaitong injection) and captopril group. MI model of rats was established by ligating left anterior descending coronary artery, and rats in sham operation group were prepared in the same way except for the ligation of coronary artery. Rats were treated with corresponding drugs for 1 month from next day after modeling. After treatment ventricular fibrillation threshold was detected, and heart weight index, left ventricular internal diameter and percentage of myocardial infarction were measured. Expression of Cx43 mRNA in myocardium was detected by real-time fluorescent quantitative polymerase chain reaction, and expression of Cx43 protein was observed by immunohistochemical method.

RESULTS

Compared with the sham operation group, ventricular fibrillation threshold decreased significantly, heart weight index and left ventricular internal diameter increased, while expressions of Cx43 mRNA and protein decreased remarkably in the model group (P<0.01). Compared with the model group, ventricular fibrillation threshold was increased significantly, heart weight index, left ventricular internal diameter and percentage of myocardial infarction were decreased significantly in the YQHX group and captopril group (P<0.05 or P<0.01). When it comes to expression of Cx43, both Cx43 mRNA and protein expressions were increased remarkably in the YQHX group compared with the model group (P<0.05 or P<0.01), while only density mean and integral optical density of Cx43 protein expression were increased significantly in the captopril group (P<0.05). The enhancements on Cx43 mRNA and positive area sum of Cx43 protein induced by YQHX drugs were stronger than those induced by captopril (P<0.05).

CONCLUSION

Shengmai injection and Xuesaitong injection have beneficial effects on ventricular fibrillation threshold in rats with MI. The mechanism is related with improving heart structure and reducing Cx43 expression after MI.