Effect of vitamin D3 on diabetic nephropathy in rats

Abstract

Objective This work aimed to investigate the possible protective effects of active vitamin D3 (calcitriol) on the kidney of streptozotocin-induced type 2 diabetes rats. Background Diabetic nephropathy (DN) is a leading cause of irreversible renal damage. Calcitriol has anti-inflammatory and antiproliferative effects. Kidneys have vitamin D receptors, so calcitriol may modulate DN. Materials and methods A total of 40 male Wistar albino rats were fed on high fat and sugar diet for 6 weeks. Eight rats were used as a control group (G). Group 1 received single dose of citrate buffer and oral coconut oil. Induction of diabetes mellitus was done in the rest (32 rats) by intraperitonial injection of single dose of streptozotocin (30 mg/kg/body weight). The diabetic rats were classified into four equal groups (eight/each). Group 2 had diabetic untreated rats that received coconut oil orally. Group 3 had diabetic rats that received subcutaneous injection of isophane insulin (10 IU/kg/day). Group 4 had diabetic rats that received calcitriol (0.03 μg/kg/day/oral). Group 5 had diabetic rats that received both insulin and calcitriol in similar dose and regiment as in groups 3 and 4 for 4 weeks. The following examinations were done: (a) body weight, kidney weight, and systolic blood pressure; (b) biochemical measurements including serum urea, creatinine, creatinine clearance, microalbuminuria, blood glucose, insulin, advanced glycation end products, and transforming growth factor-β1; and (c) histopathological and immunohistochemical of kidney tissues for caspase-3 expression. Results The results showed significant increase of glucose, insulin, advanced glycation end products, urea, creatinine, creatinine clearance, microalbuminuria, transforming growth factor-β1, and systolic blood pressure of G2. Histopathological results revealed marked changes and increased expression of caspase-3 of G2 compared with G1. In contrast, biochemical, histological, and immuonohistochemical features in groups 3, 4, and 5 showed significant improvement compared with G2. Conclusion It is concluded that calcitriol has protective effects against DN in rats.