The Effect of Vitamin D on Cellular Pathways of Diabetic Nephropathy

摘要

Background:Diabetic nephropathy is one of the most important microvascular complications and a majorcause of morbidity and mortality in diabetic patients. This study was designed to investigate the effect ofvitamin D on the expression of three key genes involved in the development of diabetic nephropathy.Methods: Twenty-four male Sprague–Dawley rats were randomly divided into three groups. The first groupserved as control and the other two groups received intraperitoneal injections of 45 mg/kg STZ to developdiabetes. The groups were treated for four weeks either with placebo or two vitamin D injections of 20,000IU/kg. Serum glucose, insulin, and HbA1c levels, and AGE cellular receptor (RAGE), aldose reductase (AR)and glutamine: fructose-6-phosphate aminotransferase (GFAT) gene expression were assessed in kidney tissueat the end of the experiment.Results:Vitamin D treatment resulted in a significant increase in insulin concentration, which could improvehyperglycaemia in diabetic rats. Serum HbA1c decreased slightly but insignificantly following the vitamin Dinjections. In addition, expression of GFAT, a key regulatory enzyme in the hexosamine pathway, wassignificantly reduced following vitamin D administration.Conclusions: Vitamin D may reduce diabetic nephropathy not only by improving blood glucose and insulinlevels, but also by modulating hexosamine pathways in kidney.