phytoestrogens and Hypertrophy--Left-Ventricular

To investigate the protective effects of daidzein (DD) on ventricular remodeling in rats with myocardial hypertrophy induced by pressure overload and its mechanism.. 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 DD 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) and Na+ -K+ -ATPase, Ca2+ -ATPase in left ventricle were quantified with spectrophotometry and the angiotension II (Ang II) in left ventricle and serum was messured with radioimmunoassay.. After treatment of the left ventricular with DD, vs aorta-contricted model group, NO content, cNOS and Na+ -K+ -ATPase, Ca2+ -ATPase 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.. DD 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 Ang II.

Topics: Angiotensin II; Animals; Hypertrophy, Left Ventricular; Isoflavones; Male; Myocardium; Nitric Oxide; Phytoestrogens; Random Allocation; Rats; Rats, Wistar; Ventricular Remodeling

Previously, we demonstrated that intact female rats fed a standard rodent diet containing soybean products exhibit essentially no adverse left ventricular (LV) remodeling in response to aortocaval fistula-induced chronic volume overload. We hypothesized that phytoestrogenic compounds in the diet contributed to the female cardioprotection. To test this hypothesis, four groups of female rats were studied: sham-operated (Sham) and fistula (Fist) rats fed a diet with [P(+)] or without [P(-)] phytoestrogens. Eight weeks postfistula, systolic and diastolic cardiac function was assessed by using a blood-perfused, isolated heart preparation. High-phytoestrogen diet had no effect on body, heart, and lung weights, or cardiac function in Sham rats. Fistula groups developed LV hypertrophy, which was not reduced by dietary phytoestrogens [1,184 +/- 229 mg Fist-P(-) and 1,079 +/- 199 mg Fist-P(+) vs. 620 +/- 47 mg for combined Sham groups, P < 0.05]. Unstressed LV volume increased in Fist-P(-) rats (428 +/- 16 vs. 300 +/- 14 microl Sham, P < 0.0001), but it was not different from Sham for Fist-P(+) animals (286 +/- 17 microl). Fist-P(-) rats developed increased ventricular compliance (5.3 +/- 0.8 vs. 2.3 +/- 0.3 microl/mmHg Sham, P < 0.01), whereas Fist-P(+) rats had no change in compliance (2.8 +/- 0.4 mul/mmHg). Intrinsic ventricular contractility was maintained in the Fist-P(+) rats, but it was reduced (P < 0.001) in the Fist-P(-) rats [systolic pressure-volume slope: 1.04 +/- 0.03, 0.60 +/- 0.06, and 0.99 +/- 0.08 mmHg/microl, for Fist-P(+), Fist-P(-), and Sham, respectively]. These data indicate that dietary phytoestrogens contribute significantly to female cardioprotection against volume overload-induced adverse ventricular remodeling and that studies evaluating gender differences in cardiovascular remodeling must consider the influence of dietary phytoestrogens.

Topics: Animals; Aortic Diseases; Arteriovenous Fistula; Cardiac Output, Low; Cardiotonic Agents; Chronic Disease; Diet; Female; Hyperemia; Hypertrophy, Left Ventricular; Myocardial Contraction; Phytoestrogens; Rats; Rats, Sprague-Dawley; Sex Characteristics; Vena Cava, Inferior; Ventricular Remodeling