Background Researches indicated that etiology and epidemiology of pertussis toxin (PTX)dependent experimental autoimmune uveoretinitis(EAU)model are very different with human uveoretinitis owing to the influence of PTX on immune.Our previous study has established lipopolysaccharide (LPS),an endotoxin,which instesad of PTX,mediated EAU model.However,the exact roles of LPS and PTX in EAU still remained unclear.Objective This study was to investigate the roles of LPS and PTX in EAU model.Methods Twenty SPF C57BL/6(H-2b) mice were assigned to 0 d-PTX-EAU group,7 d-PTX-EAU group,0 d-LPS-EAU group and 7 d-LPS-EAU group using random number table method.The mice were immunized with interphotoreceptor retinoid-binding protein 1-20(IRBP 1-20) emulsified in complete Freund adjuvant (CFA),and concurrently with or on day 7 postimmunization,LPS or PTX was injected in the footpad or intraperitoneally respectively.Delayed-type hypersensitivity (DTH) of the mice was evaluated by measuring the ear thickness 48 hours after IRBP was injected into the ear pinna,and lymphocyte proliferation was assessed by tritiated thymidine uptake.Retinal histopathological examination was performed and scored based on criteria of Caspi.The use and care of experimental animals complied with Regulation for the Administration of Affair Concerning Experimental Animals by State Science and Technology Commission.Results Serious infiltration of inflammatory cells,disorder of entire retinal structure and retinal folds were seen in the mice of the 0 d-PTX-EAU group and 7 d-LPS-EAU group on 21 days after injection of PTX or 14 days after injection of LPS,and severe vitritis and a few granuloma-like lesions were found in the 0 d-PTX-EAU group.However,only mild vasodilatation or less retinal folds were found in the 7 d-PTX-EAU group and 0 d-LPS-EAU group.The pathological scores in the mice of the 0 d-PTX-EAU group and 7 d-LPS-EAU group were higher than those of the 7 d-PTX-EAU group and 0 d-LPS-EAU group (all at P ＜ 0.05).The ear thickness was (62.600 ± 3.362) μm,(60.000±2.345) μm,(30.400± 1.817) μm and (32.800 ± 1.643) μm in the 0 d-PTX-EAU group,7 d-PTX-EAU group,0 d-LPS-EAU group and 7 d-LPS-EAU group,showing a significantly difference among the 4 groups (Fgroup =259.751,P=0.000),and the ear thicknesses of 0 d-PTX-EAU group and 7 d-PTX-EAU group were significantly higher than those of the 0 d-LPS-EAU group and 7 d-LPS-EAU group (all at P＜0.05).The lymphocyte proliferation was strongly enhanced in PTX-EAU groups,and the radiation count per minute (cpm) was (16 150.000±799.218)/min and (16 120.000±729.383)/min in the 0 d-PTX EAU group and 7 d-PTX EAU group,and (8 348.000±258.979)/min and (8 540.000±81.548)/min in the 0 d-LPS EAU group and 7 d-LPS EAU group respectively,with a significant difference among the PTX-EAU groups and LPS-EAU groups (Fgroup =316.978,P=0.000).Conclusions LPS and PTX play different roles during the EAU formation.LPS may be involved in the breakdown of blood-retina barriers (BRB).%背景 研究表明,使用百日咳毒素(PTX)诱导的传统实验性自身免疫性葡萄膜视网膜炎(EAU)模型在病原学和流行病学上与人类葡萄膜炎的发病环境有明显差异,且PTX本身可影响免疫应答.我们先前的研究已成功建立了内毒素——脂多糖(LPS)诱导的EAU模型,但PTX与LPS在EAU模型中的不同作用尚不清楚. 目的 比较在不同免疫阶段注射PTX和LPS对EAU诱导的不同影响,探讨LPS和PTX在葡萄膜视网膜炎中的作用机制. 方法 将SPF级6～8周龄C57BL/6(H-2 b)小鼠20只采用随机数字表法随机分为0 d-PTX-EAU组、7 d-PTX-EAU组、0 d-LPS-EAU组和7 d-LPS-EAU组,分别于人类光感受器间维生素A类结合蛋白多肽片段1-20(IRBP 1-20)及完全弗氏佐剂(CFA)免疫小鼠后即刻或第7天在小鼠足底注射10 g/L LPS 30 μl或腹腔内注射1.0 mg/L PTX 0.5 ml,分别建立PTX和LPS诱导的EAU模型.于免疫后第19天,耳廓皮内分别注射IRBP 1-20,48 h测量模型鼠耳廓厚度,比较两种模型小鼠的迟发型超敏反应(DTH);制备小鼠脾脏细胞匀浆,用3H脱氧胸苷(3H TdR)掺入法比较各组小鼠的特异性淋巴细胞增生反应;收集小鼠视网膜组织行苏木精-伊红染色,观察各组小鼠视网膜的炎症表现并参照Caspi标准进行炎症评分,对不同模型组小鼠的检测结果进行比较. 结果 0 d-PTX-EAU组和7 d-LPS-EAU组小鼠均出现典型的葡萄膜视网膜炎病理损害,可见明显的炎性细胞浸润、视网膜皱褶和脱离及视网膜全层结构排列紊乱,0 d-PTX-EAU组小鼠玻璃体炎和肉芽肿反应略重于7 d-LPS-EAU组;而7 d-PTX-EAU组小鼠仅见视网膜血管轻度扩张,0 d-LPS-EAU组小鼠可见少量视网膜血管扩张和个别区域的视网膜折叠.0 d-PTX-EAU组和7 d-LPS-EAU组小鼠的EAU评分明显高于7 d-PTX-EAU组和0 d-LPS-EAU组,差异均有统计学意义(P＜0.05).0 d-PTX-EAU组和7 d-PTX-EAU组小鼠耳廓厚度分别为(62.600±3.362) μm和(60.000±2.345) μm,均明显高于0 d-LPS-EAU组的(30.400±1.817) μm和7 d-LPS-EAU组小鼠的(32.800±1.643) μm,4个组间的总体差异有统计学意义(F分组=259.751,P=0.000).0 d-PTX-EAU组和7 d-PTX-EAU组小鼠体外培养的淋巴细胞克隆数显著增加,其3H TdR掺入值(cpm)分别为(16 150.000±799.218)/min和(16 120.000±729.383)/min,均明显高于0d-LPS-EAU组的(8 348.000±258.979)/min和7 d-LPS-EAU组的(8 540.000±81.548)/min,4个组间小鼠淋巴细胞增生的差异有统计学意义(F分组=316.978,P=0.000). 结论 免疫的同时注射PTX和免疫后第7天注射LPS均可诱导典型的EAU,LPS在EAU中的作用与PTX不同,主要作用于免疫的效应阶段,可能与血-眼屏障的破坏有关.
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