HMGB1表达水平对实验性结肠炎小鼠Th1/Tc1细胞反应的影响

摘要

目的：观察高迁移率族蛋白B1（HMGB1）的表达水平对实验性结肠炎小鼠辅助性T细胞1/细胞毒性T细胞1（Th1/Tc1）细胞反应的影响。方法将BALB/C小鼠分为乙醇对照组、模型组和丙酮酸乙酯（EP）干预组，后两组采用2，4，6-三硝基苯磺酸（TNBS）灌肠建立小鼠结肠炎模型。每天进行疾病活动指数（DAI）评分，于造模后第7天处死小鼠，观察结肠组织病理学损伤情况；流式细胞术分析脾脏、肠系膜淋巴结Th1/Tc1细胞比例的变化，酶联免疫吸附试验（ELISA）法检测血清和结肠组织中HMGB1、干扰素γ（IFN-γ）的表达水平。结果与乙醇对照组比较，模型组小鼠DAI评分、镜下组织病理学损伤评分均明显升高，差异均有统计学意义（P＜0.01）；同时，外周血和结肠组织中HMGB1、IFN-γ水平，脾脏、肠系膜淋巴结中Th1/Tc1细胞比例也明显高于乙醇对照组，差异均有统计学意义（P＜0.01）。与模型组比较， EP干预治疗1周后，EP干预组小鼠血清和结肠组织HMGB1水平明显降低，DAI评分下降，镜下组织病理损伤明显减轻，差异均有统计学意义（P＜0.05）；伴随脾脏、肠系膜淋巴结Th1/Tc1细胞比例的下降，血清和结肠组织中IFN-γ水平降低，差异均有统计学意义（P0.01）。结论 HMGB1可作为内源性免疫刺激剂诱导促进Th1/Tc1细胞反应亢进，进而参与实验性结肠炎小鼠的致病。%Objective To investigate the expression level of high-mobility group box 1 protein (HMGB1) on helper T1/cytotoxic T cell 1(Th1/Tc1) in experimental colitis mice. Methods The BALB/c mice were randomly divided into ethanol control group,model group and ethyl pyruvate(EP) intervention group. The colitis model in the latter two groups was induced by the ene-ma of 2,4,6-trinitro-benzene sulfonic acid(TNBS). The disease activity index(DAI) score was daily evaluated. Mice were killed on 7 d after model construction. The colonic tissue pathological damage situation was observed. The flow cytometry was applied to examine the percentages of Th1//Tc1 cells in spleen as well as in mesenteric lymph nodes (MLN). The blood and colonic tissue ex-pression levels of HMGB1 and IFN-γwere measured by ELISA. Results The DAI and microscopic histopathological damage score in the model group were significantly increased compared with the ethanol control group (P<0.01);meanwhile the levels of HMGB1 and IFN-γin peripheral blood and colonic tissue and the percentages of Th1//Tc1 cells in spleen and MLN were signifi-cantly higher than those in the ethanol control group,the differences were statistically significant(P<0.01). After 1 week EP inter-vention,the HMGB1 level in serum and colonic tissue in the EP intervention group was significantly decreased,the DAI score was declined and microscopic histopathologic damage was obviously alleviated,the differences were statistically significant(P<0.05);with the percentage decrease of Th1/Tci cells in spleen and MLN,serum and colonic tissue IFN-γexpression was decreased,the difference was statistically significant(P<0.01). Conclusion HMGB1 may serve as the endogenous immunologic stimulant to in-duce and promote Th1/Tc1 cell hyperreaction,thus involves in pathogenesis of experimental colitis mice.