Abstract: Objective To explore protective effect of procyanidins on myocardial tissue damage in the rats with type Ⅱ diabetes and its mechanism.Methods SD rats were randomly divided into control group,diabetes model group,low,moderate and high dose procyanidins groups.Low dosage streptozocin(STZ,30 mg/kg) was used to induce type Ⅱ diabetes model of rat.Procyanidins at doses of 50,100,and 200 mg/kg was administered with stomach gavage for 12 weeks.Blood sugar and fat and heart function of the rats were detected.Immuno-histochemistry methods were used to determine levels of nuclear factor-κB(NF-κB),tumor necrosis factor-alpha(TNF-α),intercelluar adhesion molecualr-1 (TCAM-1),monocyte chemoatracttant protein-1(MCP-1) in myocrdial tissue of the rats.Results Compared with the controls,blood sugar and blood fat increased significantly in diabetic rats(P< 0.01).The levels of NF-k B,TNF-a,ICAM-1,and MCP-1 in myocardial tissue of diabetic rats increased significantly (P< 0.05).Compared with the diabetes model,blood sugar,triglyceride,total cholesteral,and low -density lioprotin declined significantly (P< 0.05),while high-density lipoprotein increased significantly (P<0.05) in the rats with porcyanidins treatment.In addition,the left ventricular end-diastolic pressure was declined significantly(P< 0.05) and left indoor pressure rise rate,±dp/dt_max were elevated(P< 0.05) for the rats treated with procyanidins.The levels of NF-κB,TNF-α,ICAM -1,and MCP-1 in moderate dose procyanidins treatment group were 11.24,0.19,4.57,and 3.15,with significant reductions (P< 0.05).Conclusion Procyanidins have protective effects on myocardial tissue in rats with type Ⅱ diabetes and the effects may related to the reductions of blood sugar and lipids and the inhihition of inflummatory reaction.