摘要背景 研究表明,调节性T细胞(Treg)是一类负向调控免疫应答的T细胞亚群,在维持免疫稳态和免疫耐受方面发挥重要作用.自身免疫性葡萄膜炎是一种免疫性眼病,Treg细胞在自身免疫性葡萄膜炎发生和发展过程中的调控作用尚不完全清楚. 目的 观察Treg细胞在实验性自身免疫性葡萄膜炎(EAU)大鼠发病过程中的动态变化.方法 选取84只6～8周龄SPF级Lewis大鼠,采用随机数字表法随机分为模型组和对照组.模型组于大鼠双后足垫、腹部双侧及背部皮下注射光感受器间维生素A类结合蛋白(IRBP)1177-1191、结核菌素(TB)、完全弗氏佐剂(CFA)和PBS混合乳化剂共300μl,对照组大鼠以同样方法皮下注射等容量不含IRBP的TB与CFA乳化剂.分别于造模后第9、13、18、23、28、35、48天观察模型组和对照组大鼠的眼部炎症症状并根据严重程度进行炎症评分.于造模后上述时间点分别处死模型组及对照组大鼠各6只,采用常规组织病理学方法观察各组大鼠眼部虹膜、睫状体和视网膜组织形态变化;分离大鼠脾脏淋巴细胞,采用流式细胞术检测大鼠脾脏悬液中Treg细胞特异性标志物Foxp3标记细胞比例;采用实时荧光定量PCR法检测大鼠脾脏淋巴细胞中Foxp3 mRNA相对表达量变化. 结果 免疫后第8天模型组大鼠虹膜血管扩张充血,开始出现眼部炎症表现,免疫后第13天虹膜血管明显扩张,前房可见渗出和积脓,瞳孔区有膜样渗出,炎症评分最高,为(3.75±0.42)分,之后眼部炎症反应逐渐减轻,至免疫后第23天炎症反应接近消失,造模后第7、11、13、15、17、19、21天间模型鼠眼炎症反应评分总体比较差异有统计学意义(F=81.709,P＜0.001).对照组大鼠眼部检查正常.组织病理学观察发现,模型组大鼠虹膜、睫状体、视网膜等组织有中性粒细胞、淋巴细胞和单核细胞浸润,组织结构排列疏松,以免疫后第13天最为明显,此后逐渐减轻,至免疫后第23天虹膜、睫状体和视网膜组织结构接近正常,炎性细胞浸润消失.流式细胞技术检测发现,免疫后第13、18、23、28、35、48天模型组大鼠脾脏Foxp3标记细胞比例分别为(5.50±0.64)％、(13.36±0.98)％、(10.34±0.79)％、(9.58±1.02)、(6.73±0.81)％和(5.58±0.47)％,明显高于对照组的(2.80±0.38)％、(3.36±0.53)％、(3.65±0.57)％、(3.37±0.43)％、(3.33±0.50)％和(3.13±0.61)％,差异均有统计学意义(t=-6.272、-15.556、-11.910、-9.753、-6.154、-5.491,均P＜0.01).模型组和对照组造模后各时间点大鼠脾脏淋巴细胞中Foxp3 mRNA的相对表达量变化与Foxp3标记细胞比例变化趋势基本一致. 结论 EAU大鼠葡萄膜炎的发病及转归与Treg细胞数量和功能变化密切相关.

abstractsBackground Studies show that regulatory T cells (Treg) are a kind of T cell subsets to negatively regulate immune response,and play an important role in maintaining immune homeostasis and immune tolerance.Autoimmune uveitis is an autoimmune disease,the regulation of Treg cells in pathogenesis and progression of autoimmune uveitis is not fully unelucidated.Objective This study was to observe the dynamic changes of Treg in experimental autoimmune uveitis (EAU) rats and explore the role of Treg cells in the pathological process of EAUrats.Methods Eighty four 6-8 week-old SPF Lewis rats were randomly divided into model group and control group.The mixed emulsifier of interphotoreceptor retinoid-binding protein (IRBP)1177-1191,tuberculin (TB),complete Freund adjuvant (CFA) and PBS (300 μl) was subcutaneously injected in double rear foot pad,abdominal side and back,and only equal amount of TB,CFA and PBS emulsifier was used in the same way in the control group.Ocular inflammation symptoms was examined at 9,13,18,23,28,35 and 48 days after modeling and scored based on the severity of the inflammatory.Six rats of each group were sacrificed in above time points respectively for the histopathological examination of iris,ciliary body and retinas by haematoxylin-eosin staining.The lymphocytes were isolated and cultured from rat spleens,and the proportion of Foxp3-labelled cells,a specific marker of Treg cells,was assayed by flow cytometry.The relative expression level of Foxp3 mRNA in the lymphocytes detected by using realtime quantitative PCR (RT-PCR).The use and care of the rats complied with the ARVO Statement.Results Eye inflammatory response appeared at 8 days after immunization,showing vasodilation and hyperemia of rat iris in the model group,and the response peaked at 13 days,with exudation and hypopyon in the anterior chamber.The highest inflammatory scores were 3.75±0.42 at day 13,and the ocular inflammation reaction was gradually relieved after that and disappeared at 23 days after immunity.A significant difference in ocular inflammatory scores of model rats was found among different time points (F =81.709,P ＜ 0.001);while no inflammatory symptom was observed in the control group.Histopathology examination showed obvious infiltration of inflammatory cells in the iris,ciliary body and retinas in model rats,including neutrophils,lymphocytes and mononuclear cells.The proportion of Foxp3-labelled cells in spleen lymphocytes was (5.50 ± 0.64)％,(13.36 ± 0.98)％,(10.34 ± 0.79)％,(9.58 ± 1.02)％,(6.73 ±0.81)％ and (5.58 ± 0.47) ％ in the model group on day 13,18,23,28,35,48 respectively,with statistically significant differences in comparison with (2.80 ± 0.38) ％,(3.36 ± 0.53) ％,(3.65 ± 0.57) ％,(3.37 ± 0.43) ％,(3.33±0.50)％ and (3.13±0.61)％ in the control group (t=-6.272,-15.556,-11.910,-9.753,-6.154,-5.491,all at P＜0.01).The change trend of Foxp3 mRNA expression was consistent to the dynamic change of the proportion of Foxp3-labelled cells.Conclusions The pathogenesis and development is closely associated with the dynamic changes of CD4+ CD25 + Foxp3+ Treg cells in EAU rats.