Effect Of Kurarinone On Intestinal Mucosal Macrophage Function In Irritable Bowel Syndrome

BackgroundIrritable bowel syndrome（IBS）is characterized with abdominal pain,bloating,changes in bowel habits and stool property,which is a chronic gastrointestinal disease.The etiology and pathogenesis of this disease are unknown now.It has been reported that intestinal mucosal inflammation plays an important role in IBS,and macrophages are involved in the development of intestinal mucosal inflammation.Kurarinone（KAR）,is a kind of flavonoid extracted from sophora flavescens,which has anti-inflammatory and anti-cancer effects.However,it is not clear whether KAR regulates macrophages function in IBS.PurposeTo investigate the effect of KAR on regulating the function of intestinal mucosal macrophages in IBS,and to provide a basis for the research of KAR in the treatment of IBS。MethodsEstablish a mouse model of IBS induced by 2,4,6-trinitrobenzenesulfonic acid solution（TNBS）.After injecting KAR intraperitoneally,the visceral hypersensitivity was assessed by colorectal dilatation-αbdominal withdrawal reflex（AWR）and visceromotor response（VMR）.Intestinal motility alteration and intestinal barrier function were evaluated by colonic transportation test and intestinal permeability test.This study detected the expression of inflammatory cytokines in mouse colon tissues and colon macrophages by q RT-PCR.In addition,the phenotype and function of colon macrophages were analyzed by flow cytometry,and the effect of KAR on lipopolysaccharide（LPS）-stimulated mouse bone marrow-derived macrophage function was studied.ResultTNBS-induced IBS mouse model was successfully established.After KAR treatment,it was found that AWR,VMR score,and bristol stool grade of IBS mice were decreased,and the time of the black stool was delayed after administering intragastrically with active carbon in the stomach.The fluorescence intensity of FITC-dextran and LPS expression in serum of mice with IBS were significantly decreased,and the intestinal myeloperoxidase（MPO）expression was also significantly decreased after injecting KAR intraperitoneally.The pro-inflammatory factors such as TNF-α,IL-1β,IL-6,et al in the colon,colon macrophages and bone marrow-derived macrophages of KAR-treated mice were significantly decreased and the anti-inflammatory factors such as Arg-1,IL-10,et al were up-regulated.The pro-inflammatory subsets（CD45⁺CD11β⁺CD11c^-Ly6G^-F4/80⁺L y6C⁺MHCII^-）of colon macrophages were down-regulated and the anti-inflammatory subsets（CD45⁺CD11β⁺CD11c^-Ly6G^-F4/80⁺Ly6C^-）were up-regulated in KAR-treated mice.The surface activation markers CD86 and CD80 of bone marrow-derived macrophages（BMDM）were down-regulated by KAR-treated.Then co-cultured KAR-treated BMDM with na（?）ve CD4+T cells,the results showed that T cell activation was suppressed by KAR-treated macrophages either inhibited T cell proliferation and activation.ConclusionThis study proved that KAR alleviates clinical presentations of IBS by regulating the phenotype and function of intestinal mucosal macrophages in mice with IBS,providing new evidence that KAR may be used as immunomodulatory therapy for IBS.