Vitamin D3 Pretreatment Alleviates Renal Oxidative Stress And Regulates Renal In(?)ammatory Responses In Lipopolysaccharide-induced Acute Kidney Injury

Objective: Increasing evidence demonstrates that reactive oxygen species plays important roles in sepsis-induced acute kidney injury.This study investigated the effects of Vit D3 pretreatment on renal oxidative stress and renal inflammatory responseds in sepsis-induced acute kidney injury.Methods: Mice were intraperitoneally injected with lipopolysaccharide(LPS,2.0mg/kg)to establish an animal model of sepsis-induced acute kidney injury.In Vit D3 +LPS group,mice were orally pretreated with three doses of Vit D3(25 mg/kg)at 1,24 and 48 h before LPS injection.Renal function,GSH,MDA,BUN,renal in?ammatory cytokines,chemokines,icam-1,vcam-1 and cox-2 were analyzed.Results: Mice were intraperitoneally injected with lipopolysaccharide(LPS,2.0 mg/kg)to establish an animal model of sepsis-induced acute kidney injury.In Vit D3 + LPS group,mice were orally pretreated with three doses of Vit D3(25 mg/kg)at 1,24 and 48 h before LPS injection.As expected,oral pretreatment with three daily recommended doses of Vit D3 markedly elevated serum 25(OH)D concentration and efficiently activated renal VDR signaling.Interestingly,LPS-induced renal GSH depletion and lipid peroxidation were markedly alleviated in Vit D3-pretreated mice.LPS-induced serum and renal nitric oxide(NO)production was obviously suppressed by Vit D3 pretreatment.In addition,LPSinduced renal protein nitration,as determined by3-nitrotyrosine residue,was obviously attenuated by Vit D3 pretreatment.Further analysis showed that LPS-induced up-regulation of renal inducible nitric oxide synthase(inos)was repressed in Vit D3-pretreated mice.LPS-induced up-regulation of renal p47phox and gp91 phox,two NADPH oxidase subunits,were normalized by Vit D3 pretreatment.In addition,LPS-induced down-regulation of renal superoxide dismutase(sod)1 and sod2,two antioxidant enzyme genes,was reversed in Vit D3-pretreated mice.Finally,LPS-induced tubular epithelial cell apoptosis,as determined by TUNEL,was alleviated by Vit D3 pretreatment.Vit D3 pretreatment signifcantly alleviated LPS-induced reduction of renal function and pathological damage.Moreover,Vit D3 pretreatment attenuated LPS-induced renal in?ammatory cytokines,chemokines and adhesion molecules.In addition,pretreatment with 1,25(OH)2D3,the active form of Vit D3,alleviated LPS-induced up-regulation of in?ammatory cytokines and chemokines in human HK-2 cells,a renal tubular epithelial cell line,in a VDR-dependent manner.Further analysis showed that Vit D3,which activated renal VDR,specifically repressed LPS-induced nuclear translocation of nuclear factor kappa B(NF-?B)p65 subunit in the renal tubules.LPS,which activated renal NF-?B,reciprocally suppressed renal VDR and its target gene.Moreover,Vit D3 reinforced the physical interaction between renal VDR and NF-?B p65 subunit.Conclusion: Taken together,these results suggest that Vit D3 pretreatment alleviates LPS-induced renal oxidative stress through regulating oxidant and antioxidant enzyme genes,and a mechanistic explanation for Vit D3-mediated anti-in?ammatory activity during LPS-induced acute kidney injury.