Soy Protein Preserves Basement Membrane Integrity through a Synergistic Effect on Nephrin, Matrix Metalloproteinase and Vascular Endothelial Growth Factor

Abstract

Background/Aims: Soy protein improves renal function and prevents albuminuria in diabetic rats. This study investigates whether the renoprotective effect of soy protein is related to sustenance of basement membrane integrity. Methods: Adult male albino rats were randomized into four groups and fed one of the following semi-synthetic diets consisting of corn starch (60%) and casein (20%; CCD), fructose (60%) and casein (20%; FCD), fructose (60%) and soy protein (20%; FSD), or corn starch (60%) and soy protein (20%; CSD). Plasma chemistry and renal changes were analyzed after 60 days. Results: FCD rats displayed metabolic derangements and renal ultrastructural changes. FSD rats showed reduction in type IV collagen, tissue inhibitor for matrix metallo-proteinase-2, vascular endothelial growth factor and tumor necrosis factor-α expression and improved matrix metallo-proteinase expression. Renal architecture was preserved in these rats. Conclusion: Soy protein supplementation not only improved insulin sensitivity but also markedly attenuated renal basement membrane changes in fructose diet-fed rats. These findings provide evidence in support of the use of dietary soy protein in patients with diabetic kidney disease.