| ObjectiveUveitis is a chronic and recurrent vision-threatening eye disease that remains difficult to treat. Recurrent uveitis causes irreversible damage to the eye function, EAU(experimental autoimmune uveitis) of rats or mice is an indispensable tool to study autoimmune uveitis pathogenesis and new treatment methods,however,EAU presents one single course which is different form human uveitis relapsing course. To provide proper animal model of recurrent uveitis, we establish recurrent experimental autoimmune uveitis in rats in this study, and observe dynamically the clinical and pathological manifestations and IL-17expression in the eye.Methods1. EAU modling:To induce EAU, the antigen IRBP R16segment was emulsified1:1(vol/vol) with Complete Freund’s adjuvant (CFA), containing Mycobacterium tuberculosis H37RA, emulsified completely and injected subcutaneously into one hind footpad.2. Isolation and cultivation of R16specific T cells:10days after the EAU rats were sacrificed, and T cells were separated from the lymph nodes and spleen, and restimulated by R16in vitro culture;3. rEAU modling:R16-specific T cells were injected into naive syngeneic rats;4. Clinical observation:The clinical situations of rEAU were examined with a slit lamp biomicroscope regularly after immunization, and the inflammatory responses of the eye were scored according to Caspi criteria.5. Histopathological observation:The retinas were stained with hematoxylin and eosin(H&E) and examined by light microscopy in the group of normal rats and group of modling rats after1,2and3months respectively, retinal thicknesss was measured scientifically;6. Immunohistochemistry observation:Expression of IL-17A protein in the retina was detected by immunohistochemistry on the days indicated above.Results1. R16-specific T cells were successfully cultured in vitro. 2. Rat model of rEAU were successfully established.3. Clinical manifestations:Recurrent uveitis was induced in Lewis rats by adoptive transfer of R16-specific T cells. The disease started at4days post transfer, peaked2days later, resolved at about10days post transfer and recurred4-6days later. The rats experienced4-5episodes of disease within two months. The right and left eye of a single recipient showed a different pattern of relapse, similar as what is frequently observed in human disease.4. Histopathological observation:1) Histopathologic studies showed marked inflammatory cells infiltration in the retina. The outer nuclear layer thicknesses of the rats in one month-group was significantly thinner than that of the rats in the normal group (t=4.028, P=0.0024);2) In the two-month group, there were still a small amount of inflammatory cells in the retina. The outer nuclear layer thicknesses of this group significantly decreased compared with that of one-month group (t=13.93, P <0.0001);3) In the three-month group, retinal architectures were severely disorganized with almost the whole photoreceptor outer segment lost, and the outer nuclear layer thicknesses further significantly decreased compared with that of the two-month group (t=9.412, P<0.0001);5. Immunohistochemistry observation:1) The scores of IL-17expression in the normal group.one-month, two-month and three-month groups were0.645±0.173.1.917±0.186,1.167±0.234,0.833±0.236respectively. The differences among the groups were statistically significant (F=64.10, P<0.0001);2) IL-17expressions of each disease group were significantly higher than the normal group (P<0.01), expressions of IL-17gradually decreased with time, and the different was significantly (P<0.05).ConclusionRat rEAU can be induced by R16-specific T cells, with relapsing inflammation in anterior and posterior segments and chronic damage of retina structure. IL-17may be involved in the whole course of the disease.. |
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