Silva, InêsSolas, JoãoPinto, RuiMateus, Vanessa2022-04-272022-04-272022-04Silva IJ, Solas J, Pinto R, Mateus V. Chronic experimental model of TNBS-induced colitis to study inflammatory bowel disease. Int J Mol Sci. 2022;23(9):4739.http://hdl.handle.net/10400.21/14599IDI&CA_IPL/2019/COLITiS_ESTeSLFCT_UIDB/05608/2020. FCT_UIDP/05608/2020.Background: Inflammatory bowel disease (IBD) is a world healthcare problem. In order to evaluate the effect of new pharmacological approaches for IBD, we aim to develop and validate chronic trinitrobenzene sulfonic acid (TNBS)-induced colitis in mice. Methods: Experimental colitis was induced by the rectal administration of multiple doses of TNBS in female CD-1 mice. The protocol was performed with six experimental groups, depending on the TNBS administration frequency, and two control groups (sham and ethanol groups). Results: The survival rate was 73.3% in the first three weeks and, from week 4 until the end of the experimental protocol, the mice’s survival remained unaltered at 70.9%. Fecal hemoglobin presented a progressive increase until week 4 (5.8 ± 0.3 µmol Hg/g feces, p < 0.0001) compared with the ethanol group, with no statistical differences to week 6. The highest level of tumor necrosis factor-α was observed on week 3; however, after week 4, a slight decrease in tumor necrosis factor-α concentration was verified, and the level was maintained until week 6 (71.3 ± 3.3 pg/mL and 72.7 ± 3.6 pg/mL, respectively). Conclusions: These findings allowed the verification of a stable pattern of clinical and inflammation signs after week 4, suggesting that the chronic model of TNBS-induced colitis develops in 4 weeks.engInflammatory bowel diseaseTNBS-induced colitisChronic animal modelIDI&CA_IPL/2019/COLITiS_ESTeSLFCT_UIDB/05608/2020FCT_UIDP/05608/2020journal article10.3390/ijms23094739