肠系膜淋巴结Th1、Th17细胞在小鼠结肠炎模型发病中作用的研究

Pathogenic Role of Th1 and Th17 Cells in Mesenteric Lymph Node in Mice with Experimental Colitis

背景:大量研究表明细胞因子网络在溃疡性结肠炎(UC)的发病和疾病进程中起关键作用,但相关研究主要集中于肠黏膜免疫细胞方面。目的:探讨肠系膜淋巴结Th1、Th17细胞在模拟人类UC的小鼠DSS结肠炎模型发病中的作用。方法:C57BL/6小鼠饮用5%DSS溶液7 d诱导实验性结肠炎,实验过程中每天评估疾病活动指数(DAI)。于第8 d处死小鼠,ELISA法测定结肠组织IL-1β含量;分离肠系膜淋巴结细胞,以CD3/CD28单抗诱导淋巴细胞活化并以ELISA法测定细胞培养上清液中的Th1、Th17细胞因子含量,流式细胞术检测肠系膜淋巴结F4/80+CD11b+巨噬细胞和CD4+T细胞内Th1、Th17细胞因子表达。结果:结肠炎模型组DAI随实验进程而逐渐增加,于第7 d达峰值。与正常对照组相比,模型组结肠组织IL-1β蛋白表达显著上调(P<0.05),肠系膜淋巴结巨噬细胞浸润增加(P<0.001),淋巴细胞IL-17A分泌水平显著增高(P<0.05),IFN-γ分泌水平亦呈增高趋势(P>0.05),CD4+T细胞内IL-17A、IFN-γ表达显著上调(P<0.05)。结论:肠系膜淋巴结Th1、Th17细胞过度激活可能通过释放效应细胞因子诱导巨噬细胞等浸润、活化,参与介导小鼠DSS结肠炎模型的肠黏膜炎症反应和病理损伤。

Background： It has been confirmed by a large number of studies that cytokines network is critical for the patbogenesis and progression of ulcerative colitis （UC） , however, most of the studies were focused on the immune cells in intestinal mueosa. Aims： To investigate the pathogenic role of Thl and Thl7 cells in mesenteric lymph node in DSS-induced mice colitis model mimicking UC in human beings. Methods： Experimental colitis was induced by drinking 5% DSS solution for 7 days in C57BL/6 mice. Disease activity index （DAI） was assessed every day during the experimental course. All mice were sacrificed on day 8. Content of IL-I~ in colonic tissue was measured by ELISA method; cells were separated from mesenteric lymph node and then the contents of Thl and Thl7 cytokines in the cell culture supernatant of anti-CD3/anti- CD28 mAb activated lymphocytes were measured by ELISA method; F4/80＋ CD11b＋ macrophages and intraeellular expressions of Thl and Th17 cytokines in CIM ＋ T cells in mesenteric lymph node were determined by flow cytometry. Results ： DAI in mice with experimental colitis was increased gradually with the progression of disease and reached the peak until day 7. Compared with the normal controls, expression of IL-1β protein in colonic tissue in model mice was significantly up-regulated （ P 〈 0.05 ） ; macrophage infiltration in mesenteric lymph node （ P 〈 0. 001 ）, production of IL- 17A （ P 〈 0.05 ） and IFN-γ （ P 〉 0. 05 ） by lymphoeytes, and intracellular expressions of IL-17A and IFN-γ, in CIM ＋ T cells （P 〈 0.05 ） were increased significantly. Conclusions： Excessive activation of Thl and Th17 cells in mesenteric lymph node might mediate intestinal inflammation and pathological damage in mice with DSS-induced experimental colitis through producing effector cytokines to induce activation and infiltration of immune cells such as macrophages.