Effects of 1,25-dihydroxyvitamin D3 on macrophage chemo taxis inhibitory factor and nuclear factor-κB/P65 in obstructive nephropathy rats

Abstract

Objective To investigate the expression of macrophage migration inhibitory factor (MIF) and nuclear factor-κB/P65 (NF-κB/P65) in the kidneys of unilateral ureteral occlusion (UUO) model rats and the effect of 1,25-dihydroxyvitamin D3 on the expression. Method The cell model of obstructive nephropathy was established by renal tubular epithelial cells treated with TGF-beta 1. Thirty healthy adult male SD rats were randomly divided into 3 groups: sham operation group (n=10), UUO group (n=10) and 1,25-dihydroxyvitamin D3 group (n=10, UUO rats treated with 1,25-dihydroxyvitamin D3 by lavage 2 days before operation). The rats in sham group and UUO group were treated with equal normal saline by lavage. Serum creatinine (Scr) and histopathological changes were tested at week 2. The expressions of collagen Ⅳ (ColⅣ), macrophage marker antigen ED-1, MIF and NF-κB/P65 in renal issue were measured by immunohistochemistry. The MIF mRNA was detected by real-time PCR and the protein expressions of MIF, NF-κB inhibitor α (IKBα) and p-IKBα were measured by Western blotting. In renal tubular epithelial cells (NRK52E) the expressions of MIF and NF-κB were detected by immunocytochemistry, and the the protein expression of MIF and the activation of IKBα were teasted by Western blotting. Results Compared with those in sham group, in model group rats had increaced Scr, tubulointerstitial damage area and expressions of ED-1 and Col Ⅳ, and up-regulated mRNA and protein expressions of MIF (all P <0.05). Moreover, the amount of NF-κB/P65 nuclear positive cells and p-IKBα expression were significantly increased while the expression of IKBα decreased in model group (all P <0.05). NRK52E cells had higher expressions of MIF, NF-κB and p-IKBα, and lower IKBα in model group than those in control group (all P <0.05). After the application of 1,25-dihydroxyvitamin D3, those above effects were inhibited (all P <0.05). The results of cell model and animal model were in agreement. Conclusions The expressions of MIF and the activation of NF-κB/P65 in UUO rats increased significantly. 1,25-dihydroxyvitamin D3 may ameliorate the progression of renal tubulointerstitial inflammation and renal fibrosis by intervening the expression of MIF, inducing phosphorylation of IKBα and decreasing the activation of NF-κB/P65. Key words: Calcitriol; Disease model, animal; Chemokines; NF-kappa B; Nephritis, interstitial