Objective:To study the effect of tanshinoneⅡA on the cell signal transduction system protein kinase B(Akt) in rats with hypertrophy of the myocardium induced by partial constriction of the thoracic aorta. Methods:Rat models of myocardial hypertrophy were established by the thoracic aorta partial constriction method. Forty-eight rats were randomly divided into the sham-operative group,the model group,the valsartan treatment group,and the low-,medium-,and high-dose tanshinone treatment groups.The heart mass index(HMI),left ventricular mass index(LVMI),ejection fraction(EF),left ventricular posterior wall(LVPW),and interventricular septal thickness(IVS) were detected by high-frequency ultrasonography.The myocardial fiber diameter(MFD) was detected by HE staining,and the contents of p-Akt and p-Gsk3βin the myocardium were detected by Western blot.Results:Compared with the sham-operative group,the levels of HMI,LVMI,LVPW,IVS,and MFD were increased respectively in the other groups(P<0.05);the contents of p-Akt and p-Gsk3βwere also increased in the other groups.Compared with the model group,the levels of HMI,LVMI,LVPW,IVS,and MFD were decreased respectively in all treatment groups(P<0.05);the contents of p-Akt and p-Gsk3βwere decreased in all treatment groups as well.There was no significant difference,however,among the low-,medium-,and high-dose tanshinone treatment groups and the valsartan treatment group(P>0.05).Conclusion:TanshinoneⅡA can prevent myocardial hypertrophy by its action on the protein kinase B(Akt) signaling pathway. Method:Rat models of myocardial hypertrophy were established by the thoracic aorta partial Constriction method. Forty-eight rats were randomly divided into the sham-operative group, the model group, the valsartan treatment group, and the low-,medium-,and high-dose tanshinone treatment groups.The heart mass index (HMI), Left ventricular mass index (LVMI), ejection fraction (EF), left ventricular posterior wall (LVPW), and interventricular septal thickness (IVS) were detected by high-frequency ultrasonography. The myocardial fiber diameter (MFD) was detected by HE staining, And the contents of p-Akt and p-Gsk3βin the myocardium were detected by Western blot.Results:Compared with the sham-operative group,the levels of HMI,LVMI,LVPW,IVS,and MFD were increased respectively in the other groups( P<0.05) The contents of p-Akt and p-Gsk3βwere also increased in the other groups.Compared with the model group, the levels of HMI, LVMI, LVPW, IVS, and MFD were decreased in all treatment groups (P<0.05); The contents of p-Akt and p-Gsk3βwere decreased in all treatment groups as well.There was no significant difference,however,among the low-,medium-,and high-dose tanshinone treatment groups and the valsartan treatment group (P>0.05 ).Conclusion:TanshinoneIIA can prevent myocardial hypertrophy by its action on the protein kinase B(Akt) signaling pathway.