P075 Characterisation and structural analysis of a new murine model to study postoperative fibrotic recurrence in Crohn’s disease combining ileocecal resection with chronic colitis

Abstract Background The prevention of postoperative fibrotic recurrence in Crohn’s disease is still an unsolved problem the management patients undergoing bowel resection due to intestinal strictures. Appropriate murine models are needed examine effect surgery associated factors as well mechanical and microbial alterations after ileocecal on development disease. Methods We developed a model combining chronic dextrane sodium sulfate(DSS)-colitis with resection. 9 11-week-old C57BL/6 wild-type mice were exposed 1% DSS via drinking water for one week followed by using microsurgical technique. After surgery, recovered which two more cycles DSS-administration performed, now 1.5% DSS. Between DSS-cycles recovery was implemented. Histology performed distal ileum, anastomotic area, proximal colon, colon. Results inflammation (proximal colon: median score 5 vs. 0; p < 0.001, 3 = 0.003) fibrosis scores 2 0.008) higher colon DSS-colitis compared without colitis. Furthermore, histomorphometric parameters such proportionate collagen area mean 6.6% 2.6%; 5.4% 3.7%; 0.17) submucosal thickness 127.4µm 39.7µm; 71.5µm 37.2µm; 0.049) significantly Interestingly, most profound inflammatory changes found No small intestine. Conclusion combination colitis led within Histopathological features prominent opposed known results from model, where wall worsen towards thus hypothesize that altered physiology lower gastrointestinal tract responsible these findings. Continuing research this might enable examination mechanisms recurring