溃疡性结肠炎小鼠外周血和结肠组织中Tfh、Tfr细胞水平变化及意义

摘要

Objective To observe the changes of follicular helper T cells (Tfh cells) and follicular regulatory T cells (Tfr cells) in the peripheral blood and colon tissues of mice with ulcerative colitis,and to investigate the clinical significance.Methods Twenty male Kunming mice were randomly divided into the normal control group and observation group.We used the 100 mg/kg trinitrobenzene sulfonic acid (TNBS) ethanol enema to prepare the ulcerative colitis models,while mice in the normal control group were given the same dose of 0.9％ sodium chloride solution enema.Each mouse was anesthetized with pentobarbital sodium after 8 days,and the mice abdominal aortic blood and colonic tissue specimens were collected.We evaluated the body weight and stool in mice by UC disease activity index (DAI).The histological changes of colonic mucosa in mice were observed by HE staining,and the damage of the colon tissue was evaluated.The percentage of CD4+ CXCR5 + Foxp3 +Tfr and CD4+ CXCR5 + PD-1 + Tfh cells in the peripheral blood were measured by flow cytometry;the percentage of CD4 + CXCR5 + Foxp3 + Tfr and CD4 + CXCR5 + PD-1 + Tfh cells in the colonic tissues were measured by triple immunofluorescence staining;the protein expression of PD-1 in the colonic tissues was determined by Western blotting.Results The disease activity index (DAI),histological score,the percentage of Tfh cells in the peripheral blood,and the ratio of Tfh/Tfr cells were significantly higher in the observation group,while the percentage of Tfr cells was lower than those of the control group (all P ＜ 0.05).Compared with the control group,the proportion of Tfh cells and the expression of PD-1 protein in the colorectal tissues of the observation group were higher,but the proportion of Tfr cells was lower (all P ＜ 0.05).Conclusion The proportion of Tfh cells in the peripheral blood and colon tissues of mice with ulcerative colitis is high,and the proportion of Tfr cells is low,both of which may be involved in the pathogenesis of ulcerative colitis.%目的 观察溃疡性结肠炎小鼠外周血及结肠组织中滤泡辅助性T细胞(Tfh)和滤泡调节性T细胞(Tfr)的水平变化,并探讨其临床意义.方法 将20只雄性昆明小鼠按随机数字表法均分为正常对照组、观察组.观察组用100 mg/kg三硝基苯磺酸(TNBS)乙醇溶液灌肠制备溃疡性结肠炎模型,正常对照组予相同剂量的0.9％氯化钠溶液灌肠.造模第8天,两组给予水合氯醛按腹腔注射麻醉,采集腹主动脉血及结肠组织标本.采用UC疾病活动指数(DAI)评价小鼠体质量、大便情况;HE染色观察小鼠结肠组织病理变化,并对结肠组织损伤情况进行评分;用流式细胞术检测小鼠外周血CD4+ CXCR5+ Foxp3+ Tfr、CD4+ CXCR5+ PD-1+ Tfh细胞比例;用三色免疫荧光标记法检测小鼠结肠组织中CD4+ CXCR5+ Foxp3+ Tfr、CD4+ CXCR5+ PD-1+ Tfh细胞比例;用Western blotting法检测结肠组织中程序性死亡因子1(PD-1)蛋白表达.结果 观察组DAI、组织损伤评分、外周血中Tfh细胞比例、Tfh/Tfr高于正常对照组,Tfr细胞比例低于正常对照组(P均＜0.05);观察组结肠组织中Tfh细胞比例及PD-1蛋白表达高于正常对照组,Tfr细胞比例低于正常对照组(P均＜0.05).结论 溃疡性结肠炎小鼠外周血及结肠组织中Tfh细胞比例高、Tfr细胞比例低,二者可能参与溃疡性结肠炎的发病过程.