Effects of curcumin on renal OPN/NF-κB pathway in diabetic rats

Objective To investigate the effects and mechanisms of curcumin on renal OPN/NF-κB pathway in experimental type 2 diabetic rats.Methods Forty rats were randomly divided into sham operated rats group(S,n=8) and operated rats group(n=32) which underwent nephrectomy of left kidney,then divided into uninephrectomized group(1/2Nx,n=8) and experimental group(n=24).Two weeks after operating experimental rats were raised with high-fat and high-sugar food.Sixteen rats which met the criterion of diabetic mellitus were divided into diabetic nephropathy rats(DN,n=8) and diabetic nephropathy rats treated with curcumin(DN+Cur,n=8) which lasted six weeks.After 6 weeks,the blood sugar,creatinine clearance,24 h urinary albumnin excretion,renal pathology,the expression of NF-κB/p65 and CD68(by immunohistochemistry) and OPN mRNA(by RT-PCR) were compared among the groups.Results Treatment with curcumin could markedly decrease Ccr and urinary albumin excretion compared with untreated diabetic rats(P0.05).Whereas the blood sugar had no difference between them(P0.05).After treatment with curcumin renal pathologic changes were reduced and the expression level of NF-κB/p65 protein in nuclei and CD68 positive cells dropped than in DN group(P0.05).OPN mRNA expression was significantly diminished in DN+Cur group than DN group(P0.05).Conclusion Curcumin may alleviate the inflammation process by down-regulating OPN mRNA expression and inhibiting NF-κB/p65 transduction into nuclei.