SOY PROTEINS PREVENT HEART REMODELING IN WISTAR RATS ON HIGH SODIUM CHLORIDE DIET

Abstract Background and Aims Increased salt intake has been linked to a number of poor effects, such as myocardial remodeling [1], independently of blood pressure level. Yet, many aspects of this remodeling are not well understood. The aim of the study was to find echocardiographic myocardial changes in Wistar rats on high sodium chloride (NaCl) diet, as well as to prove protective effects of diet, containing soy proteins. Method 28 male Wistar rats (age of 2.5-3.0 months) were enrolled in the observational prospective study (4 month) and subdivided into several groups. 1) Standard diet-Control group (C, n = 8, 20.16% protein of animal origin and 0.34% NaCl); 2) High salt diet (n = 10, 8% NaCl); 3) Low-protein diet (n=10, 10% soy protein (SUPRO 760) and 8% NaCl). Tail systolic blood pressure (BP) measurement, as well as echocardiographic examination were performed in anesthetized rats. Statistical analysis was performed with STATISTICA 10 software package. Fisher's LSD test was used. The significance level was <0.05. All data are presented as mean ± SEM. Results Keeping rats on a diet with 8% NaCl did not lead to significant changes in blood pressure (group 2 - 138.0 + 5.0, group 3 - 134.0 + 5.0 mm Hg), compared to C (135.0 + 5.0 mm Hg). On the contrary, left ventricle back wall width in rats of group 2 was significantly higher (1.83 ± 0.09 mm, p <0.02), than in C (1.49 ± 0.10 mm) or animals from group 3 (1, 47 ± 0.09mm). The values of end systolic left ventricle size, interventricular septum width, mitral valve systolic movement and tricuspid valve systolic movement in group 3 were significantly lower (1.67 ± 0.08 mm, 2.18 ± 0.13 mm, 2.70 ± 0.23 mm), than in group 2 (3.26 ± 0.33mm, p <0.037; 2.00 ± 0.12mm, p <0.043; 2.67mm ± 0.15, p <0.0124; 3.56 ± 0.34mm , p <0.0148, respectively). At the same time, left ventricular chamber size and thickness of interventricular septum did not differ significantly. In C animals, mitral valve movement (1.96 ± 0.09 mm; p <0.0008) and tricuspid valve movement (2.35 ± 0.07 mm; p<0.0012) were significantly lower than in rats of group 2 but not differed much from the values found in group 3. Conclusion High sodium containing diet does not necessarily lead to the development of arterial hypertension in Wistar rats, but may cause heart remodeling, while soy proteins counteracts the development of left ventricle hypertrophy, even in case of high sodium consumption.