淋巴细胞功能相关抗原-1调节Treg细胞对炎症性肠病的影响

摘要

背景:Treg细胞在炎症性肠病(IBD)中主要发挥免疫保护作用,淋巴细胞功能相关抗原-1(LFA-1)参与了Treg细胞的分化和功能发挥.目的:探讨LFA-1调节Treg细胞对IBD的影响,明确LFA-1在IBD发生中的作用.方法:将LFA-1基因缺失小鼠和相同遗传背景野生型小鼠各20只分别随机分为对照组和炎症组,炎症组以饮用4.5％DSS溶液诱导结肠炎模型.观察各组小鼠一般情况和结肠组织学表现,流式细胞术检测外周血CD4+、Treg细胞比例,real time PCR检测结肠组织Foxp3 mRNA表达,ELISA法检测血清IL-17A、TGF-β1、IL-10水平.结果:LFA-1缺失炎症组实验过程中有2只小鼠死于消化道出血,体质量下降较野生型炎症组显著.LFA-1基因缺失小鼠外周血CD4+、Treg细胞比例低于野生型小鼠,其中LFA-1缺失炎症组伴TGF-β1、IL-10分泌减少；LFA-1缺失炎症组与野生型炎症组间外周血Treg细胞比例无明显差异.野生型和LFA-1缺失炎症组血清IL-17A、TGF-β1、IL-10水平和结肠组织Foxp3 mRNA表达均高于相应对照组.结论:LFA-1参与了IBD时Treg细胞的分化和迁移.LFA-1基因缺失小鼠对DSS结肠炎的耐受性差于野生型小鼠,可能与其Treg细胞分化和相关细胞因子分泌受到影响有关.%Background:It has been widely accepted that Treg cells exert an immunoprotective effect in inflammatory bowel disease (IBD),and lymphocyte function-associated antigen-1 (LFA-1) is involved in the differentiation and suppressor function of Treg cells.Aims:To investigate the effect of LFA-1 on IBD by regulating Treg cells and verify the role of LFA1 in the pathogenesis of IBD.Methods:Twenty LFA-1 gene knockout (LFA-1-/-) mice and 20 wild type mice with same genetic background were randomly divided into control group and colitis group,respectively.Colitis model was induced by drinking 4.5 ％ DSS solution.General condition and histology of the colon were observed in each group.Percentages of CD4 + and Treg cells in peripheral blood were analyzed by flow cytometry.Expression of Foxp3 mRNA in colonic tissue was detected by real time PCR,and serum levels of IL-17A,TGF-β1 and IL-10 were measured by ELISA method.Results:In LFA-1-/-colitis group,two mice died of intestinal hemorrhage,and the weight loss in survived mice was more significant than that in wild type colitis group.Percentages of CD4 + and Treg cells in peripheral blood in LFA-1-/-mice were lower than those in wild type mice,accompanied by reduced TGF-β1 and IL-10 secretion in LFA-1-/-colitis group.No significant difference was seen in percentage of Treg cells in peripheral blood between LFA-1-/-and wild type colitis groups.Serum levels of IL-17A,TGF-β1 and IL-10,as well as expression of Foxp3 mRNA in colonic tissue were increased in wild type and LFA-1-/-colitis groups when compared with wild type and LFA-1-/-control groups,respectively.Conclusions:LFA-1 is involved in the differentiation and migration of Treg cells in IBD.LFA-1-/-mice are less tolerant to DSS-induced colitis than wild type mice,which may be related to the effect of LFA-1 on differentiation and cytokines secretion of Treg cells.