the effect of vitamin d on cellular pathways of diabetic nephropathy

Background: diabetic nephropathy is one of the most important microvascular complications and a major cause of morbidity and mortality in diabetic patients. this study was designed to investigate the effect of vitamin 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 group served as control and the other two groups received intraperitoneal injections of 45 mg/kg stz to develop diabetes. the groups were treated for four weeks either with placebo or two vitamin d injections of 20,000 iu/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 tissue at the end of the experiment.results: vitamin d treatment resulted in a significant increase in insulin concentration, which could improve hyperglycaemia in diabetic rats. serum hba1c decreased slightly but insignificantly following the vitamin d injections. in addition, expression of gfat, a key regulatory enzyme in the hexosamine pathway, was significantly reduced following vitamin d administration.conclusions: vitamin d may reduce diabetic nephropathy not only by improving blood glucose and insulin levels, but also by modulating hexosamine pathways in kidney.