<正>Objective:To investigate the effect of berberine

one of the main alkaloids of Rhizoma coptidis

on myocardial morphology and the expressions of cyclin-dependent kinase 9（Cdkg）and cyclin T1 protein in the myocardium of type 2 diabetic rats.Methods:Type 2 diabetes mellitus rats were induced by an injection of 35 mg/kg streptozotocin（STZ） and a high-carbohydrate/high-fat diet for 16 weeks.Diabetic rats were given low-

middle-

high-dose berberine（75

150

300 mg/kg）

fenofibrate（100 mg/kg）and rosiglitazone（4 mg/kg）for another 16 weeks

respectively.The myocardium structure was observed with hematoxylin & eosin（H&E）staining and Cdk9 and cyclin T1 protein expressions were detected by immunohistochemistry.Results:Middle-dose

high-dose berberine improved myocardial hypertrophy and interstitial fibrosis of diabetic rats.Cdk9 and cyclin T1 protein were significantly lower in diabetic myocardium than in control one（P<0.01）

and middle-dose

high-dose berberine and fenofibrate obviously increased both Cdk9 and cyclin T1 expression to near control level（P<0.01）.Conclusion:Berberine modulates Cdk9 and cyclin T1 protein expression in diabetic myocardium which may contribute to ameliorate myocardium damage.