Effect of Losartan on the Expression of Angiotensin-converting Enzyme 2 in Myocardium in Renal Hypertensive Rats

Objective To investigate the effects of losartan on the expression of angiotensin-converting enzyme 2 (ACE2) and angiotensin-converting enzyme (ACE) in myocardium of hypertensive rats.Methods Sprague-Dawley male rats were underwent two kidney one clip(2K1C) operation and treated with losartan(10 mg/kg,n=12),(20 mg/kg,n=12),(30 mg/kg,n=12),for 4 weeks.Twelve SD rats received sham operation served as controls.Myocardial morphology was observed by HE staining;the expressions of ACE2 and ACE protein levels were detected with Western blot assay.Results Compared with sham group,the expression of myocardial ACE2 was decreased significantly [(0.49±0.01) vs (0.88±0.03),P0.01],and the expression of ACE was increased obviously[(1.21±0.07) vs (0.61±0.02),P0.01] with concomitant increases in SBP.All three doses of losartan decreased the blood pressure and LVM/weight ratio in hypertensive rats significantly (P0.05).Losartan increased ACE2 and decrease of ACE expressions in dose-dependent manner.The myocardial remodeling index (heart weight/body weight) was closely related to the ACE/ACE2 ratio(P0.01).Conclusion The reversing of ACE2 and ACE expression in myocardial tissue may be one of the mechanisms governing losartan antihypertensive and myocardial protection effect in the 2K1C hypertensive rats.