Autophagy and mTOR Pathways Mediate the Potential Renoprotective Effects of Vitamin D on Diabetic Nephropathy

Abstract

Introduction. Not only is diabetic nephropathy (DN) the most common cause of end-stage renal disease worldwide, but it also increases the risk of mortality up to fourteen times compared to normoalbuminuric diabetic patients. Aim. The aim of the current study was the evaluation of the renoprotective effects of vitamin D in DN and the possible interplay between autophagy and mTOR pathways. Materials and Methods. Fifty male Wistar albino rats were divided (10/group) into control, DN group, insulin-treated DN group, vitamin D-treated DN group, and combined insulin and vitamin D-treated DN group. Assessments of systolic blood pressure, albuminuria, creatinine clearance, serum glucose, insulin, urea, creatinine, inflammatory cytokines, oxidative stress markers, and rat kidney gene expression of mTOR were performed. Histopathological and immunohistochemical assessments of autophagy marker LC3 in rat kidneys were also performed. Results. DN was associated with significant increases in SBP, urinary albumin, serum glucose, urea, creatinine, inflammatory cytokines, MDA, and mTOR gene expression (P0.05). Conclusion. It has been concluded that vitamin D is a potent adjuvant therapy in treatment of DN via downregulation of mTOR gene expression, stimulation of autophagy, and antioxidant, anti-inflammatory, and hypotensive effects.