Abstract: To investigate the effect of Losartan and A779 on myocardial interstitial fibrosis in diabetic cardiomyopathy (DCM). MethodsThirtynine male Wistar rats were intraperitoneally injected with streptozocin (STZ) once to induce hyperglycemia. After 12 weeks of STZ injection, rats whose blood glucose was higher than 16.7mmol/L and who had polydipsia, hyperphagia and polyuria were randomly divided into 3 groups: the DCM group, the losartan group and the A779+Losartan group. The DCM group was subjected to perfusion of normal saline into the stomach once daily, the losartan group perfusion of losartan once daily, and the A779+Losartan group perfusion of losartan and injection of A779 through the tail vein once daily. At the end of the experiment, LVIDs, LVIDd, E/A, LVEF and FS were determined by ultrasound. Then the collagen level was determined by Masson staining, and the mRNA expression of angiotensinconvertion enzyme 2 (ACE2) was determined by real-time RT-PCR. ResultsBy the end of the experiment, the LVIDs, LVIDd and the collagen level of the losartan group and the A779+Losartan group were lower than those of the DCM group (P＜0.01), also the E/A, FS, LVEF levels and the expression of ACE2 mRNA of the losartan group and the A779+Losartan group were higher than those of the DCM group(P＜0.01). The LVIDs, LVIDd and collagen content of the A779+Losartan group were higher than those of the losartan group(P＜0.05), and E/A, FS and LVEF of the A779+Losartan group were lower than those of the losartan group(P＜0.05). However the expression of ACE2 mRNA had no difference between the losartan group and the A779+Losartan group. ConclusionsLosartan amelioorates the myocardial interstitial fibrosis via Ang-(1.7).

Key words: Losartan, Angiotensin(1.7), Angiotensinconvertion enzyme2, A779, Diabetes mellitus, Cardiomyopathy, Rat, Wistar