Abstract: Objective:To investigate the variation of the immune functions in ulcerative colitis(UC)rats,including the immune globulin,complement and red blood cell(rBC).Methods:Forty-eight rats were randomly divided into control group model group 1,model group 2 and model group 3,with 12 rats in each.The model groups were given 0.5 ml 30% alcohol enema containing 20 mgtrinitrobenzene-sulfonic acid(TNBS)to construct UC rat models and the control group was given 0.5 ml physiological saline enema.The changes of the immune globulin complement and rBC immune function were detected.Results:The content of IgA and rBC circulating immune complexes in the blood serum of the model group increased predominantly at the first,third and seventh week as compared with those of the normal group(P0.01);the content of IgG in the model group increased predominantly at the first and third week as compared with that in the normal group(P0.01).The expressions of IgA,rBC circulating immune complexes and IgG were the highest in the model group at the first week,which began to decrease at the third one,and the expression at the seventh and the first week was statistically different(P0.01).IgM had no significant deviation between the model groups and the control group(P0.05),but C3 and red blood cell surface C3b receptor in the model group were lower than those in the control group at the first,third and seventh week(P0.01).The content of C4 in the model group was lower at the first and the third week than that in the control group(P0.01).Conclusions:The changes of immune globulin,complement and rBC immune function reveal that abnormal increasing of immunoresponse may lead to deposition of circulating immune complexes in the intestinal mucosa of the UC rats and activate local allergy.