Hoda Derakhshanian - Department of Biochemistry, Genetics and Nutrition, School of Medicine, Alborz University of Medical Sciences, Karaj, Iran. & Dietary Supplements and Probiotic Research Center, Alborz University of Medical Sciences, Karaj, Iran.
Abolghassem Djazayery - Department of Community Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
Mohammad Hassan Javanbakht - Department of Cellular and Molecular Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
Mohammad Reza Eshraghian - Department of Biostatistics, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Abbas Mirshafiey - Department of Pathobiology, School of Public Health, Tehran University of Medical Sciences, Tehran, Iran.
Mahnaz Zarei - Department of Cellular and Molecular Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
Ehsan Alvandi - Department of Cellular and Molecular Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.
Ehsan Djalali - Department of Veterinary, Science and Research Branch of Islamic Azad University, Tehran, Iran.
Mahmoud Djalali - Department of Cellular and Molecular Nutrition, School of Nutritional Sciences and Dietetics, Tehran University of Medical Sciences, Tehran, Iran.

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.

Diabetes Mellitus, Hexosamine pathway, Nephropathy, Vitamin D.