Abstract
Purpose :
Several studies have indicated that inflammatory process is involved in the pathogenesis of diabetes, however little is known for an effect of immune responses impaired in diabetic condition on development of autoimmune diseases. Experimental autoimmune uveitis (EAU) is widely accepted as a model of endogenous uveitis of suspected autoimmune etiology in humans. In this study, we investigated effects of hyperglycemia on development of EAU using type 1 diabetic mice.
Methods :
In this study, we used Ins2Akita (Akita) mice, which spontaneously develop Type 1 Diabetes Mellitus by a mutation in the insulin 2 gene. C57BL/6 (B6) mice and Akita mice were subcutaneously immunized with 200 µL total CFA supplemented with M. tuberculosis strain H37RA to 2.5 mg/mL emulsion containing 2 mg/mL human IRBP 1-20 (1:1 wt/vol) and administration of 0.5 µg pertussis toxin (i.p.). Clinical scores of EAU were performed by funduscopic examinations on day 0, 7, 14, 21 after immunization and histological scoring was evaluated on day 21. Splenocytes were also obtained on day 21 and were stimulated with 0, 5, 10 µg/mL human IRBP 1-20 for 72 hr. Supernatants were collected and contained cytokines (IL-2, IL-4, IL-6, IL-17A, and IFN-γ) were measured by Bio-Plex Multiplex Immunoassay System. In addition, cell-surface expression of CD4 and Foxp3, and production of cytokines were analyzed by flow cytometory.
Results :
Clinical scores of EAU in Akita mice (0.23±0.53) were significantly lower than those in B6 mice (1.75±0.91). There was also statistically difference in histological scores between Akita mice (0.11±0.52) and B6 mice (1.1±0.22). IFN-γ production by splenocytes was apparently reduced in Akita mice compared with B6 mice (935±514 pg/ml vs. 2031±1237 pg/ml), although IL-17A production was higher in Akita mice (1084±35 pg/ml) than in B6 mice (739±140 pg/ml). There were no differences in IL-2, IL-4, and IL6 production between Akita mice (323±75, 62±25, and 126±18 pg/ml) and B6 mice (396±8.4, 107±4.0, and 212±0.8 pg/ml). Similar results were obtained by flow cytometory for splenic CD4+ cells. On the other hand, population of CD4+ Foxp3+ T cells in the spleen was significantly augmented in Akita mice (9.03±0.91%) compared with B6 mice (4.80±1.04%).
Conclusions :
It is indicated that EAU in Akita mice was downregulated by impaired Th1 cell activation rather than Th17 cells via augmentation of Treg cells.
This abstract was presented at the 2022 ARVO Annual Meeting, held in Denver, CO, May 1-4, 2022, and virtually.