The link between vitamin D status and NF-κB-associated renal dysfunction in experimental diabetes mellitus

Abstract

BackgroundType 1 diabetes (T1D) is accompanied by numerous side effects, including renal dysfunction. Mounting evidence suggests that overactivation of nuclear factor ĸB (NF-κB) is one of the key triggers of diabetes-associated chronic kidney disease. Vitamin D3 is considered as a strong modulator of a number of transcription factors, including NF-κB. The purpose of our study was to assess the contribution of NF-κB to type 1 diabetes (T1D)-induced kidney dysfunction and to determine if vitamin D3 supplementation can correct the changes associated with T1D. MethodsThe following animal groups were used: control, diabetic (induced by single i.p. injection of streptozocin at dose 55 mg/kg b.w.), T1D group treated with vitamin D3 (600 IU/kg b.w.), T1D group treated with NF-κB inhibitor – BAY 11‐7082. ResultsDiabetes led to a decrease in serum 25(OH)D that was accompanied by down-regulation of vitamin D receptor (VDR) expression and up-regulation of hydroxylases CYP24A1 and CYP27B1 synthesis in the kidneys. Diabetes activated the transcription factor NF-κB and increased cleaved (p17) caspase-3 level in renal tissue. Restoration of vitamin D status normalized vitamin D-endocrine system, decreased NF-κB activation and caspase-3 protein level in the kidneys of diabetic animals. BAY 11–7082 partially mimicked the effects of vitamin D3. General significanceVitamin D3 supplementation counteracts diabetes-induced kidney damage, most likely through VDR-mediated inhibition of NF-κB activation.