Objective: To study the suppression of Schistosoma japonicum eggs against the trinitrobenzene sulfonic acid (TNBS)-induced colitis in mice.
Methods: 50 female BALB/c mice (6-8 week-old) were randomly divided into normal control group, ethanol control group, schistosome egg immunized control group, TNBS-induced colitis group and TNBS-induced colitis with egg immunization group. In TNBS-induced colitis with egg immunization group, mice were immunized 4 times with 10,000 schistosome eggs by intraperitoneal injection with one-week interval. On day 6 after the last immunization the mice were induced by TNBS and the body weight, histological change on colon and level of cytokines of mice were observed in egg-immunized and -unimmunized colitis mice.
Results: The unimmunized mice developed significant inflammation in colon with bloody mucus feces and decreased body weight after TNBS induction. Distinct hyperemia, edema and transmural inflammatory infiltration accompanied with ulceration were shown in colon. The level of IFN-gamma was (3.47 +/- 0.87) ng/ml and IL-4 was (146.06 +/- 45.76) pg/ml. However, in egg-immunized mice, the inflammation was suppressed greatly and the body weight recovered soon after TNBS induction. The production of IL-4 was enhanced to (598.50 +/- 135.90) pg/ml, and IFN-gamma was significantly diminished to (1.53 +/- 0.51) ng/ml.
Conclusion: S.japonicum eggs protect mice from colitis induced by TNBS.