Fig. 6. CD69⁺ Tregs attenuated DSS-induced IBD.

IBD was induced by administering DSS in acidified drinking water, 2% (w/v) for 10 days. The day that mice started to drink DSS was regarded as day 0. For the treatment of IBD, 1 × 10⁶ CD4⁺CD25⁺CD69⁺ Tregs or CD4⁺CD25⁺CD69^- Tregs were sorted from the splenocytes of the Il10^+/+ or Il10^−/−mice and mice were injected i.v on day 2. a Body weight loss was recorded daily. Each point represents average weight data pooled from 8 mice ± SD. Control group: the mice fed with normal water; PBS group, mice with drinking water containing 2% DSS and intravenously treated with PBS on day 2. b Disease activity index (DAI, combined score of body weight, bleeding, and stool consistency) was evaluated daily. Each point represents average DAI data pooled from 8 mice. c Appearance and statistical analysis of colonic length on days 9. d Histological appearance of the colons from individual groups of mice 10 days after induction. The colonic sections were stained with H&E (magnification ×200). e Mouse received intravenous injection of 1 × 10⁶ /200 μl CD69⁺ Tregs or 200 μl PBS and then were killed 3 h or 6 h post injection. The colon tissues were dissected out and the cryostat colonic sections (8 μm) were stained with rabbit anti-CD69 and mouse anti-Foxp3 antibodies. The distribution of CD69⁺ Tregs in the colon tissues was detected with immunofluorescence assay. Date are representative images or expressed as the mean ± SD of three independent experiments (n = 7 per group). *P < 0.05, **P < 0.01, ***P < 0.001, ****P < 0.0001, analyzed by ANOVA or Student’s t-test