Objective:To compare the rat models of ulcerative colitis induced by 2

4

6-trinitro-benzene-sulfonic acid(TNBS) and immune-comb method.Methods:SD rats were randomly distributed into groupⅠ(immune-comb method)

groupⅡ(TNBS/ethanol)

groupⅢ(50% ethanol) and groupⅣ(control).The rats in groupⅠwere sensitized 2 times by antigen made of rabbit colon mucosa in 2-week intervals.After abrosia for 24 hours

each rat in four groups received enema of 0.65 ml different fluids

which were:TNBS 100mg/kg +50%ethanol for groupⅠand Ⅱ

50%ethanol for group Ⅲ

and normal sodium for control group.Rats were sacrificed on day 1

21 and week 8

12 after enema to observe the macroscopical focus of infection in bowels and the microscopical changes.Results:The typical erosion and ulcer changes appeared in groupⅠandⅡ

and there was accompanying pathological changes in the end piece of ileum in groupⅠ.The pathological changes for groupⅠcould keep for 8 weeks

while those for group Ⅱtrended to heal 3 weeks later.The pathological changes in groupⅢonly were hyperemia

oedema and a few anabrosis or superficial ulcer

keeped for 21days.There was no tissue damage in group Ⅳ.Conclusion:Immune-comb method is comparatively the ideal method to establish the model

because it has a good reproducibility

a long persistence time

and the pathological changes resemble more to those of man..