Vitamin D Supplementation Could Enhance the Effectiveness of Glibenclamide in Treating Diabetes and Preventing Diabetic Nephropathy: A Biochemical, Histological and Immunohistochemical Study

Diabetes mellitus is an oxidative stress-related disease characterized by hyperglycemia and a variety of complications, including nephropathy. Vitamin D has variable functions extending beyond the calcium metabolism to prevent oxidative tissue damage. We aimed to investigate whether vitamin D supplements could enhance Glibenclamide's effectiveness in treating diabetes and minimize the risk of associated pathology. Wistar rats were divided into normal control (n = 10) and diabetic (n = 30), where animals received two low doses of Streptozotocin 30 mg/kg/BW intraperitoneally to develop diabetes. The diabetic rats were then randomly divided into three equal groups: untreated, treated with Glibenclamide (0.6 mg/kg), and treated with Glibenclamide and Vitamin D3 (500 IU/kg). After eight weeks, the animals were sacrificed, and blood samples and kidney tissues were collected to evaluate biochemical, anti-oxidant, and pro-inflammatory cytokine levels and histological and immunohistochemical changes. Diabetic animals had significantly increased fasting blood glucose, lipid profile, blood urea, serum creatinine, and Malondialdehyde levels, whereas serum insulin, albumin, and the anti-oxidant enzymes superoxide dismutase and catalase were significantly decreased compared to normal control (p < 0.01). Furthermore, some renal histological changes were observed together with significantly increased immunoreactivity of anti-p53, anti-TNF-α, and anti-IL-6 antibodies when compared to the normal control. All abnormal parameters improved significantly with Glibenclamide therapy (p < 0.01), but combination therapy with vitamin D produced a much better result. In conclusion, vitamin D supplementation along with anti-diabetic medication can help prevent or reduce the severity of diabetic nephropathy due to its potent antioxidant, anti-inflammatory, and anti-apoptotic properties.