Soy protein and genistein improves renal antioxidant status in experimental nephrotic syndrome

Nephrotic syndrome is a chronic disease especially common in the childhood and adolescence. Reactive oxygen species (ROS) and free radicals have significant role in the pathogenesis of nephrotic syndrome. The aim of this study was to evaluate the effect of soy protein and genistein (main isoflavone of soybean) on renal antioxidant status of nephrotic rats.

This study was done for 8 weeks on 40 adult male Sprague-Dawley rats divided into four groups of 10 rats each. Study groups included: 1-Control, 2-Nephrotic syndrome, 3-Nephrotic syndrome+soy protein diet and 4-Nephrotic syndrome+soy protein diet+genistein. Urine protein and urine creatinine were measured. After homogenization of kidney, total antioxidant capacities (TAC), activities of catalase enzyme, the concentration of malondialdehydes (MDA) and carbolynated proteins were determined spectrophotometrically. Pathological examination was done on kidneys with light microscope. Cell viability was evaluated with MTT assay on WEHI-164 fibro sarcoma cell line. The MMP2 enzyme activity was evaluated in different concentrations of genistein.

Total antioxidant capacity was significantly increased in soy genistein. Catalase activity was significantly increased in soy and soy genistein groups. Protein carbonyl and MDA were significantly lower in soy and soy genistein groups. The scores of pathological examination showed significant improvement in soy and soy genistein groups. Genistein decreased the proliferation of the WEHI-164 fibrosarcoma cell line.

It seems that soy protein decreases kidney damages in nephrotic syndrome. Adding genistein to soy protein causes improvements in antioxidant status of kidney tissue. Genistein decreases proliferation of cell.