Different roles of endotoxin and pertussis toxin in experimental autoimmunity uveoretinitis / 中华实验眼科杂志

ABSTRACT

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).