Influence of soybeanisoflavones on hypertrophic myocardium induced by pressure overload in rats

Objective:To investigate the protective effects of soybeanisoflavones(SI) on ventricular remodeling in rats with myocardial hypertrophy induced by pressure overload and its mechanism. Methods:Myocardial hypertrophy model of rats induced by pressure overload was prepared by constricting abdominal aorta. The operated rats were randomly divided into sham operated control group ,aorta-constricted model group and three SI groups ( 30,60,120 mg·kg-1).Four weeks later, the heart-weight(HW),left ventricular weight(LVW),the ratio of HW/BW and LVW/BW(LVI) and the cardio-myocyte diameters(MD) after dyeing by HE colar were measured.The hydroxyroline, nitric oxide(NO) and the activity of nitric oxide synthetase(NOS) in left ventricle were quantified with spectrophotometry and the angiotensionⅡ(AngⅡ) in left ventricle and serum was messured with radioimmunoassay. Results:In aorta-constricted model group, The ratio of HW/BW , LVI, MD and the content of hydroxyproline and iNOS activity in the left ventricle and the content of AngII in left ventricle and serum were significantly increased, and cNOS activity and NO content in left ventricle were obviously decreased. After treatment of the left ventricular with SI, NO content, cNOS activity were significantly increased, the content of AngII in left ventricle and serum and iNOS activity and the ratio of HW/BW, LVI ,MD were significantly reduced. Conclusion:SI has protective effects on ventricular remodeling in rats with myocardial hypertrophy induced by pressure overload and its mechanism may be related to raising NO content and reducing the level of AngⅡ.