Th17细胞因子在CD大鼠结肠不同炎性时期的差异表达

Differential expression of Th17 cytokines in the colon of rats in different inflammatory periods of Crohn's disease

目的:观察不同次数三硝基苯磺酸(trinitrobenzene-sulfonic acid,TNBS)灌肠刺激对大鼠肠道炎症程度及结肠组织Th17细胞因子白介素(interleukin,IL)-6、IL-17A、IL-21、维甲酸相关孤核受体γt(retinoid-related orphan nuclear receptorγt,RORγt)表达的影响.方法:30只清洁级♂SD大鼠,160 g±10 g,随机分为正常对照组(NG)、1 wk造模组、2 wk造模组、3 wk造模组、4 wk造模组.按照Morris等方法制备克罗恩病(Crohn's disease,C D)大鼠模型,T N B S灌肠液由5%T N B S与500 m L/L的乙醇按2∶1比例混合而成,1次/wk.采用结肠一般形态和HE病理观察TNBS对结肠黏膜的病理损伤程度,荧光定量P C R、免疫组织化学等技术观察各组大鼠结肠黏膜中RORγt、IL-17A的表达,ELISA法观察血清中IL-6、IL-21含量的变化.结果:大鼠结肠IL-17A m RNA水平在第1次TNBS诱导后表达为下降,在3 wk时,IL-17A m RNA与蛋白水平明显升高(P<0.05),第4次诱导后达到最高.大鼠结肠RORγt蛋白随着刺激次数的增加而表达量逐渐增高(P<0.05),第4次诱导后达到最高(P<0.05);血清中I L-6、I L-21含量也均在1 w k时间点即开始显著上升(P<0.01),在第4周达到最高值.模型大鼠结肠组织大体形态评分和组织损伤评分显著增加(P<0.01).结论:TNBS诱导CD模型过程中,Th17细胞因子IL-6、IL-17A、IL-21、RORγt的含量随着刺激次数的增加而逐渐增加,并伴随结肠炎症程度的加重而逐渐加重.

AIM：To observe the intestinal inflammatory status and the expression of interleukin（IL）-6,IL-17 A,IL-21,and retinoid-related orphan nudear receptor γt（RORγt） secreted by Th17 cells in colon tissues of rats with trinitro-benzenesulfonic acid（TNBS） induced Crohn＇s disease.METHODS：Thirty male rats were randomly divided into a normal control group and 1-,2-,3- and 4-wk model groups.Morphological observation and HE staining were used to assess the degree of damage to the colonic mucosa.Fluorescence quantitative PCR,immunohistochemical method and other techniques were used to observe the expression of RORγt and IL-17 A in rat colonic mucosa,and ELISA method was used to detect the contents of IL-6 and IL-21 in serum.RESULTS：The level of IL-17 A mRNA in rat colon decreased at the first induction with TNBS,but the levels of IL-17 A mRNA and protein obviously increased（P〈0.05） at3 wk and reached the highest after the fourth induction.The expression of RORγt protein gradually increased after induction（P〈0.05）,and reached the highest at the fourth induction（P〈0.05）.The contents of IL-6 and IL-21 in serum obviously increased from the first week（P〈0.01）,reaching the highest at the fourth week.The colon general morphological score and tissue damage score of model rats obviously increased（P〈0.01）.CONCLUSION：During the process of Crohn＇s disease induced with TNBS,the contents of IL-6,IL-17 A,IL-21,and RORγt secreted by Thl7 cells gradually increased and the degree of colonic inflammation gradually exacerbated.