美沙拉嗪对结肠炎大鼠肠黏膜免疫反应中DCs的影响

目的观察树突状细胞（dendriticcells，DCs）在实验性结肠炎大鼠肠道免疫系统中的变化及对炎症细胞因子的影响，并探讨美沙拉嗪治疗机制。方法30只雄性大鼠建立实验性结肠炎模型，随机均分为正常对照组（NC组）、模型对照组（CC组）和美沙拉嗪治疗组（MC组）。光镜下观察大鼠结肠组织炎症并评分，检测DCs细胞表面标志物OX-62、CD83、MHC—Ⅱ和CD86分子表达率，检测伊尔氏淋巴滤泡（PP）炎症细胞因子的表达。结果NC、CC和MC组炎症评分分别为4．35±0．88、10．25±t．36和6．78±0.71，各组间均有显著差异（P〈0．05）。免疫组化示NC、CC和MC组肠系膜淋巴结DCs上OX-62表达分别为198．6±87．7、1422．1±598．2、503．2±78．4；CD83表达分别为87．6±24．4、709．2±199．6、322．7±112．3；流式细胞仪检测MHC—Ⅱ表达率分别为（26．2±7．2）％、（84．6±9．4）％和（48．1±9．0）％；CD86为（20．5±7．7）％、（80．6±8．8）％和（47．8±11．4）％，各组间均有显著差异（P〈0．05）。酶免疫分析法CC组检测PP细胞因子TNF—α、IFN-γ和IL—12表达高于NC组，而IL-10低于NC组，MC组TNF-α、IFN-γ和IL-12表达均低于CC组，但高于NC组，IL—10表达相反，各组间比较均有明显差异（P〈0．05），三组大鼠的TGF—β表达则均无差异（P〉0．05）。结论树突状细胞分化、发育与成熟，影响肠道炎症细胞因子的失平衡，可能与结肠自身免疫损伤有关；美沙拉嗪抑制DCs的活化，促进促炎因子和抑炎因子平衡。

Changes of dendritic cells in intestinal mucosa immune response of experimental colitis rats treated with mesalazine

Objective To investigate the differentiation, development and activation of dendritic cells （DCs） and the changes of inflammatory cytokines in experiment colitis rat, and to evaluate the effects of mesalazine. Methods Thirty Wistar rats were randomly divided into normal control group （NC group）, colitis control group （CC group） and mesalazine-treated group （ MC group）. Histological inflammatory score of colonic mucose were studied. Changes in phenotype and functions of DCs in mesenteric lymphoid nodes were analyzed by immunohistochemical staining or flow cytom- etry. Changes of cytokines in mucosal were analyzed by enzyme immunoassay. Results Inflammatory scores have significantly differences in NC, CC, MC group （4.35 ±0.88, 10.25 ± 1.36 and 6.78±0.71, P 〈0.05）. Expressions of OX-62 and CD83 on DCs in mesenteric lymph node by immunohistochemical staining analysis among each group were 198.6 ± 87.7, 1422.1 ±598.2, 503.2 ±78.4 and 87.6 ±24.4, 709.2 ± 199.6, 322.7 ± 112.3, respectively （P 〈 0.05）. Expressions of MHC- 11 and CD86 on DCs by flow cytometry between each group were （26.2 ± 7.2） % , （84.6 ±9.4）%, （48.1 ±9.0）% and （20.5 ±7.7）%, （80.6 ± 8.8）%, （47.8±11.4）%, respectively （P〈0.05）. TNF-α, IFN-γ and IL-12 were higher and IL-10 was lower in CC group in supernatants of Peyers＇ patches cells than those in NC group （P 〈0.05）. TNF-α, IFN-γ and IL-12 were decreased and IL-10 was increased in MC group compared with those in CC group, but expression of TGF-β had no statistical difference in three groups. Conclusion Differentiation, development, maturation of DCs and imbalance between pro-inflammatory and anti-inflammatory cytokines may play an important role in development of experimental colitis, and relate to the autoimmune damage of colonic tissues.