CB2R activation ameliorates the symptoms and colon inflammation in DSS-induced colitis mice.

C57BL/6 mice were treated with vehicle or HU 308 (1 mg/kg, i.p.) once a day from day 0 to day 8 while receiving 3% DSS, the control mice were given tap water. In another set of experiments, WT and CB2R KO mice received 3% DSS for 8 days, the control mice were given tap water. Body weight, the presence of occult or gross blood per rectum, and stool consistency were determined by two investigators blinded to the treatment groups. Postmortem, the colon was removed and pieces of colonic tissue were used for ex vivo analysis. Treatment of HU 308 significantly reduced body weight loss (A), bloody stool score (B), increment of colon length (C) and alleviated colon inflammation (D-E). n = 7 per group. **P<0.01 vs. the control group; #P<0.05 vs. the DSS + vehicle group, ##P<0.01 vs. the DSS + vehicle group. Compared with WT group, body weight loss (F), bloody stool score (G), reduction of colon length (H) and colon inflammation (I-J) were significantly increased in CB2R KO group. n = 10 per group. **P<0.01 vs. the control group; #P<0.05 vs. the WT DSS group, ##P<0.01 vs. the WT DSS group.