Effect and mechanism of soluble epoxide hydrolase inhibitor in renal fibrosis mice model / 中华肾脏病杂志

ABSTRACT

Objective To investigate the effect and mechanism of soluble epoxide hydrolase inhibitor (sEHI) for NF-κB pathway and cell circle arrest of tubular epithelial cell in unilateral ureteral obstruction (UUO) mice model.Methods Thirty-two healthy C57BL/6 male mice performed UUO surgery to induce renal interstitial fibrosis.Animals were randomly divided into 4 groupssham group (n=8),sEHI (1 mg· kg-1·d-1) group (n=8),UUO group (n=8) and UUO+sEHI (1 mg· kg-1· d-1) group (n=8).Daily sEHI [1-(1-methylsulfonyl-piperidin-4-yl)-3-(4-trifluoromethoxy-phenyl)-urea,TUPS] or 2％ DMSO was applied to mice by oral gavage from day 1 to day 14 after surgery.All mice were sacrificed at day 14 and kidneys were harvested for further analysis.The changes of renal tissue morphology and pathology were observed by Hematoxylin and eosin (HE) and sirius red staining.The expressions of sEH,nuclear factor κB p65 (NF-κB p65) and IκB were measured by Western blotting.The expressions of TNF-α,IL-1β,MCP-1,IL-6,TGF-β,CTGF,collagen-Ⅳ and α-SMA were analyzed by real-time PCR.Immunofluorescence staining of phospho-histone H3 (p-HH3) and Ki67 was performed to determine the stage of cell cycle G2/M arrest.Results The expression and activity of sEH increased in UUO group (P ＜ 0.05).Administration of sEHI inhibited activity of sEH and infiltration of inflammatory cell in tubular interstitial,as well as attenuated tubular damage and tubular interstitial fibrosis.Western blotting analysis revealed administration of sEHI inhibited up-regulated NF-κB p65 and down-regulated IκB in UUO group (P ＜ 0.05).Real-time PCR demonstrated that administration of sEHI obviously decreased the mRNA expression of cytokines and fibrosis markers,including of TNF-α,IL-1 β,MCP-1,IL-6,TGF-β,CTGF,Collagen-Ⅳ,α-SMA (P ＜ 0.05).Immunofluorescence staining showed that there were much more p-HH3 and Ki67 double positive nuclear tubular epithelial cells and interstitial cells in UUO group,compared with Sham group (P ＜ 0.05).Administration of sEHI reduced the number of double positive nuclear cell only in tubular epithelial cells (P ＜ 0.05),but not in interstitial cells.Conclusions In UUO tubular interstitial fibrosis model,sEHI inhibits the activation of NF-κB pathway by down-regulating p65 and up-regulating IκB and ameliorates the infiltration of inflammatory cells.In addition,sEHI plays anti-fibrosis effect by moderating cell cycle G2/M arrest and reducing the excrete of pro-fibrosis factors of tubular epithelial cells.