AIM:To evaluate the therapeutic effects of a probiotic supplement(Clostridium butyricum,CGMCC0313)in a chemically-induced rat model of experimental colitis. METHODS:An experimental ulcerative colitis model was established by rectal injection of oxazolone into the colon of 40 Wistar rats randomly divided into four groups.The positive control group was sacrificed 3 d after colitis onset.The remaining groups were fed daily with either 2 mL of C.butyricum(2.3×1011 CFU/L), 2 mL of mesalamine(100 g/L),or 1 mL of sodium butyrate(50 mmol/L)for 21 d.The animals’body weight, behavior,and bowel movements were recorded weekly. After sacrifice,visual and microscopic observations of pathological changes of colon tissue were made,body weight and wet colon mass index were measured and recorded,and serum levels of interleukin-23(IL-23) and TNF-αwere measured using ELISA.Expression of calcitonin gene-related peptide in colon tissue was measured by RT-PCR.Finally,changes in rat intestinal microflora status were measured in all groups. RESULTS:We found that treatment with C.butyricum lowered the serum levels of both IL-23 and tumor necrosis factor-α(TNF-α)with similar or even better efficiency than that of mesalamine or sodium butyrate. The rat intestinal flora appeared to recover more quickly in the group treated with C.butyricum than in the mesalamine and sodium butyrate groups.Finally,we found that the expression level of calcitonin gene related peptide was elevated in colon tissue in the sodium butyrate treated group but not in the C.butyricum or mesalamine treated groups,indicating a sensitization of colon following sodium butyrate treatment.CONCLUSION:In our experimental colitis model, treatment with C.butyricum CGMCC0313,a probiotic supplement,is at least as efficient as treatment with mesalamine. AIM: To evaluate the therapeutic effects of a probiotic supplement (Clostridium butyricum, CGMCC0313) in a chemically-induced rat model of experimental colitis. METHODS: An experimental ulcerative colitis model was established by rectal injection of oxazolone into the colon of 40 Wistar rats randomly divided into four groups. The positive control group was sacrificed 3 d after colitis onset. The remaining groups were fed daily with either 2 mL of C. butyricum (2.3 × 10 11 CFU / L), 2 mL of mesalamine (100 g / L) , or 1 mL of sodium butyrate (50 mmol / L) for 21 days. The animals’ body weight, behavior, and bowel movements were recorded weekly. After sacrifice, visual and microscopic observations of pathological changes of colon tissue were made, body weight and wet colon mass index were measured and recorded, and serum levels of interleukin-23 (IL-23) and TNF-αwere measured using ELISA. Expression of calcitonin gene-related peptide in colon tissue was measured by RT-PCR. in rat intestinal microflora RESULTS: We found that treatment with C. butyricum lowered the serum levels of both IL-23 and tumor necrosis factor-α (TNF-α) with similar or even better efficiency than that of mesalamine or sodium butyrate . The rat intestinal flora was to recover more quickly in the group treated with C. butyricum than in the mesalamine and sodium butyrate groups. Notably, we found that the expression level of calcitonin gene related peptide was elevated in colon tissue in the sodium butyrate treated group but not in the C. butyricum or mesalamine treated groups, indicating a sensitization of colon following sodium butyrate treatment. CONCLUSION: In our experimental colitis model, treatment with C. butyricum CGMCC0313, a probiotic supplement, is at least as efficient as treatment with mesalamine.