Myocardial Remodeling Induced By Aldosterone And Inhibited Partially By Natural Vitamin E

Objective: Heart remodeling is the main cause of chronic heart failure. It was approved that aldosterone make important function in the process of heart remodeling. Increased pressure or capacity burden hasten the secrete of aldosterone, then speeding heart remodeling. It has nothing to do with lowering blood pressure that aldosterone blockade can improve heart remodeling. Some research indicate, aldosterone promotes heart remodeling involve increasing heart oxidative stress. To establish a model of rat's heart remodeling by Aldosterone hypodermic injection, giving spironolactone and natural Vit E intragastric administration respectively in the meantime, observe the effects of extrinsic aldosterone and natural VE on oxidative stress and heart remodeling.Methonds: Thirty-two rats were randomly assigned into 4 groups,8 rats each group: namely control group, ALD group(ALD 18 ug/d hypodermic injection for 4 weeks), ALD+SPI group(ALD 18 ug/d hypodermic injection and SPI 20 mg/kg.d intragastric administration for 4 weeks),and ALD+VE group(ALD 18 ug/d hypodermic injection and natural Vit E 200 mg/kg.d intragastric administration for 4 weeks). All animals were sacrificed after 4 weeks。Ratio of left ventricular weight/body weight(LVW/BW) and heart weight/body weight(HW/BW) were detected. The activities of superoxide dismutase (SOD) in cardiomyocyte homogenate were detected by means of xanthine oxidation and thiobarbituric acid was used to determine the concentration of malondialdehyde (MDA), masson staining was used for the determination collagen volume fraction(CVF), TUNEL was used detection of cell apoptosis, immunohistochemistry was used detection of Bcl-2 and Bax.Results: Compared with control group, SOD and Bcl-2 were lower, LVW/BW, HW/BW, MDA ,AI and Bax were higher in ALD group, cardiac fibrosis was increasing, especially around vein(P<0.01). ALD+ SPI group and ALD+ VE group had less MDA ,Bax ,CVF and AI; but more SOD and Bcl-2(P<0.01). Compared with ALD group, LVW/BW and HW/BW were lower in ALD+ SPI group(P<0.01), but did not in ALD+ VE group.Conclusions:(1) Aldosterone hypodermic injection increased rat myocardial oxidative stress ;(2) Aldosterone induced rats myocardial remodeling include not only heart hypertrophy and cardiac fibrosis, but also cadiomyocyte apoptosis; (3) Aldosterone induced rats cadiomyocyte apoptosis due to its increased Bax expression and decreased Bcl-2 expression.(4) Natural VE can reverse oxidative stress and partially improve cardiac fibrosis and cardiomyocyte apoptosis induced by aldosterone in rat, but not heart hypertrophy.