Fig. 4

Exo-srIκB demonstrates the ability to suppress arthritis in the SKG mouse model. A The animal study protocol is depicted, where 11-week-old female SKG mice were treated with either Exo-Naïve or Exo-srIκB starting from the 3rd week after arthritis induction, which was achieved by injecting curdlan. Arthritis scores were assessed based on the clinical severity of arthritis in each group, with a total of nine mice per group. Two-way analysis of variance (ANOVA) was performed to determine statistical significance for the clinical score. B A representative tissue stain of the ankle joint at the end of the experiment is displayed in the right panel, along with the analysis of histological scores for inflammation. Kruskal–Wallis test with Dunn’s multiple comparisons was performed to determine statistical significance. C The number of cells exhibiting co-expression of TNF-α or IL-17A among CD4-positive T cells per high-power field (HPF) was counted. The prevalence of CD4-positive T cells co-expressing TNF-α or IL-17A was significantly reduced in the ankle joints of mice treated with Exo-srIκB compared to those receiving Exo-Naïve treatment. Over 150 cells in each field were selected, ensuring the exclusion of nonspecific signals. A Mann–Whitney U-test was performed to determine statistical significance. D Analysis of the frequencies of IFN-γ, IL-17A, and TNF-α-producing cells was conducted on SKG splenocytes. Mann–Whitney U-test was performed to determine statistical significance. The values presented are the mean ± SEM, and the symbols represent individual sample. *P < 0.05, **P < 0.01