To explore the effect of the angiotensin type 1 (AT-1) receptor antagonist, Irbesartan, on myocardial interstitial fibrosis in rats with diabetic cardiomyopathy (DCM). Thirty-nine male wistar rats were injected intraperitoneally with streptozotocin (STZ) (55 mg/kg, once) to establish a DCM animal model. After 12 weeks, the rats with blood glucose higher than 16.7 mmol/L, as well as polydipsiaa€hyperphagia and polyuria, were randomly divided into three groups: control, Irbesartan and A779+Irbesartan group. Rats in control were infused normal saline, in Irbesartan were infused Irbesartan (50 mg/kg) and in A779+Irbesartan were infused Irbesartan and were injected with A779 (100 ng/kg) once daily. At the end of the experiment, left ventricular internal dimension systole (LVIDs)a€left ventricular internal dimension diastole (LVIDd)a€E/Aa€left ventricular ejection fraction (LVEF)a€shortening fraction (FS) were measured. Then collagen content and the messenger ribonucleic acid (mRNA) expression of angiotensin-convertion enzyme 2 (ACE2) were detected. At the end of the experiment, the LVIDs, LVIDd and the collagen content of Irbesartan and A779+Irbesartan were significantly lower than control (P
