Ocular inflammation and pathological characteristics of recurrent experimental autoimmune uveitis in rat / 中华实验眼科杂志

ABSTRACT

Background Most animal models of experimental autoimmune uveitis (EAU) are single attacked procedure,with a different feature from the natural course of human recurrent autoimmune uveitis.So establishing a recurrent EAU model is necessary for the clinical study on EAU.Objective This study was to establish the recurrent EAU model in rat and investigate the ocular inflammation and pathological manifestation and interleukin-17 (IL-17)expression in the eye.Methods T cells isolated from the spleen and draining lymph nodes of Lewis rats immunized with interphotoreceptor retinoid-binding protein (IRBP) 1177-1191 peptide fragments (R16) 10 days earlier were re-stimulated with R16 in vitro and injected into naive syngeneic rats to establish the recurrent EAU models,and the normal Lewis rats were used as controls.The eyes of model rats were then examined daily for clinical signs of uveitis by slit-lamp biomicroscopy and scored Caspi's criteria.The rats were sacrificed 1 month,2,3months after injection respectively,and the retinal sections were prepared for the pathological examination by hemotoxylin & eosin staining.Immunohistochemistry was performed to detect the expression of IL-17 in the retina.Results Adoptive transfer of R16-specific T cells to Lewis rats induced recurrent uveitis.The inflammatory scores on the fourth day,the sixth day,and the inflammatory response disappeared on the tenth day after injection.However,the inflammatory reaction occurred repeatedly 4 or 5 times in the 2-month duration after that,and the right and left eyes of a single recipient showed a different pattern of relapse,and the clinical manifestations of EAU was similar to the natural course to those of human autoimmune uveitis.In the retinal specimens of 1-,2-and 3-month group,the number of inflammatory cells was gradually decreased as the time lapse.Compared with the normal group,the thicknesses of the entire retina,outer nuclear layer and inner nuclear layer decreased with a significant difference among the 4 groups (F=20.46,288.40,4.43,all P=0.00).The number of RGCs in the normal group,1-,2-and 3-month group was 231.27 ± 15.36,225.36 ± 17.79,132.18 ±9.39 and 67.45 ± 11.90,respectively,showing a significant difference among them (F=68.94,P=0.00).Immunohistochemistry showed that the scores of the IL-17 expression in the rat retina were 0.64 ± 0.17,1.92 ± 0.19,1.17 ± 0.23 and 0.83 ± 0.23,showing statistically significant difference (F=64.10,P=0.00).Conclusions The stimulation of R16-specific T cells can induce recurrent EAU in Lewis rat.Th17 is involved in the disease course.