Novel Swine Model of Colonic Diverticulosis.

The pathophysiology of colonic diverticulosis has not been completely understood. The development of appropriate animal models is essential to study diverticular disease. To date, no large animal models are available for this disease condition. The objective of this study is to develop a swine model by damaging of colon wall, combined with or without low fiber diet to mimic the pathogenesis of diverticulosis. To create a weakness on the colon wall, collagenase was applied in vivo to degrade the collagen in the colon wall. Three groups of Yucatan minipigs were included: Group 1 (n=12) underwent collagenase injection (CI) with low fiber diet for 6 months. Group 2 (n=8) underwent CI alone with standard swine diet for 6 months. Group 3 (n=12) received low fiber diet alone for 6 months. We found that diverticulosis occurred in 91.7% (11/12) of pigs in CI+diet group and 100% (8/8) in CI alone group. Moreover, around 30-75% of colon CI spots for each pig developed diverticular lesions. Diet alone for 6 months did not induce diverticulosis. The endoscopic and histological examinations revealed the formation of multiple wide-mouthed diverticular lesions along the descending colon. Our results provide convincing evidence of the high efficacy of the reduced colon wall strength caused by CI in the development of a swine model of diverticulosis. Low fiber diet consumption for 6 months had no influence on the generation time and incidence rate of diverticulosis. In this model, digestion of the collagen in the colonic wall is sufficient to cause diverticulosis.