A novel porcine model for chemically inducible Crohn’s-like reaction

Background: New animal models provide insights into the pathogenesis of different types of inflammatory bowel disease as well as novel pathways for new therapeutic options. However, the scarcity of large animal models hinders the research and development of new surgical procedures and technological devices in inflammatory bowel disease surgery. Common small animal inducible models involve chemical agents that result in the development of acute intestinal inflammation.

Objectives: To assess a novel method for the induction of Crohn’s-like colitis using intramural injection of sclerosants in a porcine model.

Methods: Seven domestic pigs underwent several experimental protocols to assess the efficacy of intramural colonic injections of two different compounds (lauromacrogol, and phenol in almond oil). Twenty-five different large bowel segments were treated with intramural injections of the compounds. The animals were followed for 6 weeks, and treated colonic segments were resected for histopathological examination.

Results: Intramural injection of lauromacrogol resulted in nonspecific, mild reactive foreign body changes only. Injection of various dosages of 5% phenol in almond oil caused a range of histopathological changes varying from focal fibrosis to Crohn’s-like reactions comprising acute and chronic infiltrates, mucosal ulceration and focal necrosis with enteric and lymphoid non-caseating granulomas.

Conclusions: Intramural colonic phenol in almond oil injection in pigs induces inflammatory reactions that histologically resemble Crohn’s disease in humans.