Improvement effects of Astragalus on ventricular remodeling in rat after myocardial infarction and its influence in expression of protein kinase C

Objective To observe the improvement effect of Astragalus(AS)Injection on the ventricular remodeling in the rats after myocardial infarction and its regulation effect on the protein kinase C(PKC),and to clarify the mechanisms.Methods The left anterior descending(LAD)branch of coronary artery of 42 healthy Wistar rats were ligated in order to establish ventricular remodeling model after myocardial infarction.36 rats survived after24 hwere divided into three groups and 12 in each group.The rats in sham operation group were given physiological saline 2 mL·d-1 by intraperitoneal injection;the rats in myocardial infarction group(model group)were given physiological saline 2 mL·d-1 by intraperitoneal injection;the rats in AS group were treated with AS Injection6g·d-1(2mL·d-1)by intraperitoneal injection.After 6 weeks the survival situation of the rats in various groups was observed.The echocardiographic examination was made to inspect the left ventricular end diastolic diameter(LVEDD),left ventricular end systolic diameter(LVESD),left ventricular ejection fraction(LVEF)and left ventricular fraction shortening(LVFS).The levels of plasma brain natriuretic peptide(BNP)of the rats in various groups were detected. Masson staining was used to determine the collagen volume fraction(CVF)of myocardium and the PKCαand PKCeexpression levels in myocardial cells were detected by immunohistochemical staining and Western blotting method.Results The number of dad rats in AS group was less than that in model group.Compared with sham operation group,the LVESD and LVEDD of the rats in model group were increased(P0.05),the LVEF and LVFS were decreased(P0.05),and the BNP lelvel was increased(P0.05).Compared with model group,the LVESD and LVEDD of the rats in AS group were decreased(P0.05),the LVEF and LVFS were increased(P0.05),and the BNP level was decreased(P0.05).Compared with sham operation group,the CVF in the myocardial cells of the rats in model group was increased(P0.05).Compared with model group,the CVF in the myocardial cells of the rats in AS group was decreased(P0.05).Compared with sham operation group,the PKC expression level in the myocardial cells of the rats in model group was increased significantly(P0.05).Compared with model group,the PKCαexpression level in the myocardial cells of the rats in AS group was decreased significantly(P0.05),and the PKCeexpression level was increased significantly(P 0.05).Conclusion AS Injection can improve the ventricular remodeling in the rats after myocardial infarction,and its mechanism may be related to up-regulating the expression of PKCeand inhibiting the expression of PKCα.