Expression and role of Tim-3 in the pathogenesis of experimental autoimmune uveitis
Objective To investigate the expression and role of T cell immunoglobulin and mucin domain-containing protein 3(Tim-3)in the pathogenesis of experimental autoimmune uveitis(EAU).Methods A total of 12 male C57BL/6J mice,aged 4 to 5 weeks,were selected and divided into the control group(n=3)and the experimental group(n=9)using a random number table.The control group(modeling time point:0 days after modeling)received no treatment,while the experimental group was induced to establish an EAU model(divided into three subgroups according to the modeling time points:7 days,14 days,and 21 days after modeling,with 3 mice in each subgroup).Firstly,the interphotoreceptor retinoid-binding protein 651-670 and complete Freund's adjuvant were fully mixed and emulsified.Then,the emulsion was subcutaneously injected into the two thighs,tail base,and neck of mice in the experimental group(each mouse received 200 µL of immune emulsion containing 500 pg of interphotoreceptor retinoid-binding protein 651-670).Subsequently,each mouse in the experimental group was also intraperitoneally injected with 1 µg of pertussis toxin.The anterior segment and fundus of mice in each group were observed and photographed under a slit-lamp microscope.The clinical and histopatho-logical scoring of these mice was conducted according to the Caspi grading scale based on the severity of inflammation.The serum levels of IFN-γ and IL-17 were measured using the enzyme-linked immunosorbent assay(ELISA),while the mRNA expression of Tim-3 in the spleen and ocular tissues was detected using the real-time quantitative polymerase chain reaction(RT-qPCR).Western blot was employed to detect the protein expression of Tim-3,and immunohistochemistry was used to examine the protein expression of Tim-3 in the spleen tissue.Statistical analysis was performed using GraphPad Prism 9.0.Results The clinical scores of the anterior segment,fundus,and histopathology of the mice increased over time after modeling,with statistically significant differences among these groups(P<0.05).The serum levels of IFN-γ and IL-17 in the mice also increased over time after modeling,with statistically significant differences among these groups(P<0.05).The relative mRNA expression of Tim-3 in the spleen and ocular tissues of the mice decreased over time after modeling,with statistically significant differences among these groups(P<0.05).The protein expression of Tim-3 in the ocular and spleen tissues showed the same pattern as its mRNA expression.Conclusion The expression of Tim-3 decreases with the exacerbation of inflammation in the progression of EAU,suggesting that Tim-3 may play a negative immunoregulatory role in the development of uveitis.