The Effect Of Losartan And A779 To Myocardial Interstitial Fibrosis In Diabetic Cardiomyopathy

ObjectiveTo investigate the effect of Losartan and A779 to myocardial interstitial fibrosis in diabetic cardiomyopathy.MethodsThirty-nine male wistar rats were injected intraperitoneally with streptozocin (STZ)once to induce hyperglycemia so as to construct a DCM model.After 12 weeks of STZ injection,the rats whose blood glucose are higher than 16.7mmol/L,as well as polydipsia,hyperphagia and polyuria,were randomly divided into 3 groups: DCM group,losartan group and A779+Losartan group.DCM group was perfused into the stomach with normal saline once daily,losartan group was perfused into the stomach with losartan once daily;and A779+Losartan group was perfused into the stomach with losartan and was injected with A779 through tail vein once daily.At the end of experiment,LVIDs,LVIDd,E/A,LVEF,FS were measured through ultrasound.Then myocardium tissues were collected,collagen content was detected by Masson staining,real-time RT-PCR was used to detect the mRNA expression of angiotensin-convertion enzyme 2(ACE2).Results1.The results of heart function LVIDs and LVIDd of losartan group and A779+Losartan group were significantly lower than that of DCM group(P＜0.01),and E/A,FS and LVEF of losartan group and A779+Losartan group were higher than that of DCM group(P＜0.01).However, the results of above are just on the contrary vs losartan group(P＜0.05).2.Masson staining of myocardiumThe collagen content of losartan group and A779+Losartan group were significantly lower than that of DCM group(P＜0.01),and the collagen content of A779+Losartan group were higher than that of losartan group(P＜0.05).3.The expression of ACE2 mRNAThe expression of ACE2 mRNA of losartan group and A779+Losartan group were higher than that of DCM group(P＜0.01),.However,there is no difference between losartan group and A779+Losartan group.Conclusions1.Losartan treatment can significantly improve heart function in DCM rats.2.Losartan treatment can significantly improve the expression of ACE2 in DCM rats.3.Losartan can significantly reduce the quality of myocardial fibrosis in DCM rats,Ang-(1-7)and its receptor involved in the effect of iosartan confirmed indirectly by Ang-(1-7)receptor antagonist A779.