Soy protein preserves basement membrane integrity through a synergistic effect on nephrin, matrix metalloproteinase and vascular endothelial growth factor.

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.