Establishment Of Chronic Colitis Animal Model In BALB/C Mice Induced By TNBS

Objective: To explore ways of the Establishment of BALB/C mice colitis animal model induced by TNBS/ethanol enema and the relation between TGF-βexpression and intestinal wall fibrosis of chronic TNBS-induced colitis in animal models.Methord: 60 BALB/C mice were randomly divided i into blank control group,50% ethanol control group,TNBS acute colitis model group,TNBS chronic colitis model I-II group. Each group have 12 mice. They were administered intracolonically one time per week in different pharmaceutical enema ,The blank control group were administered intracolonically six weeks with only 100ul saline enema, killed in7th week.50% ethanol control group were administered intracolonically six weeks with only 100ul ethanol(50%) enema, killed in 7th week.TNBS/ethanol acute colitis model group were administered intracolonically one week with 2.0mgTNBS/ethanol(50%) enema, killed in 2nd week. TNBS chronic colitis model I-II group were administered intracolonically six weeks with TNBS/ethanol(50%) enema, the model I killed in 7th week., the model II killed in 9th week. Checking the general pathological of the entire colon from killed mice, organizations of 5cm from the anus were taken to HE staining, VG staining and TGF-βimmunohistochemical staining, and scoredResult:DAI in all groups(in order of blank control group,50% ethanol control group,TNBS acute colitis model group,TNBS chronic colitis model I-II group,)respectively is 1.38±1.18,2.25±1.67,9.00±1.69,4.13±1.36,3.25±1.98;Inflammatory scores is 0.63±0.74,1.88±1.25,8.00±3.11,3.25±1.67,3.43±1.84;Survival rate is 100%,100%,67%,75%,75%;We can found that from the results: the DAI score and intestinal histopathological score of the TNBS acute colitis model group,TNBS chronic colitis model I-II group were higer than blank control group,50% ethanol control group.TGF-βexpression levels of the mouse intestinal were detected with Immunohistochemistry.The results showed that TGF-β1 was increased in the TNBS acute and chronic colitis animal models. However, TGF-β1 was increased more significantly in TNBS chronic colitis model I-II group. observed intestinal fibrosis in every group with V-G staining.According to mice intestinal fibrosis score,the score of TNBS chronic colitis model I-II group were higher than blank control group,50%ethanol control group,TNBS acute colitis model group.This indicated that there are a large number of layers of collagen protein in submucosa and serosa of TNBS chronic animal model. with inherent muscle Obvious thickened.Conclusion:(1)Different concentrations of TNBS used for different duration of the enema, can create different types of colitis mouse model,including acute colitis and chronic colitis with fibrosis. (2) fibrosis and inflammation were no significant regression after stoping the TNBS enema in the Chronic colitis model .which indicate this is a a stable fibrosis model.(3) TGF-β1 expression and the intestinal wall fibrosis was positively correlated, TGF-β1 expression was no significant decline after stoping the TNBS enema, suggesting that TGF-β1 may be one of the mechanisms of fibrosis.