Effect of berberine on Cdk9 and cyclin T1 expressions in myocardium of diabetic rats

Abstract

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 (Cdk9) 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). Conclusions Berberine modulates Cdk9 and cyclin T1 protein expression in diabetic myocardium which may contribute to ameliorate myocardium damage.