Novel swine model of colonic diverticulosis

Abstract

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 was to develop a swine model by damaging the colon wall, combined with or without a 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 a low-fiber diet for 6 mo, group 2 (n = 8) underwent CI alone with a standard swine diet for 6 mo, and group 3 (n = 12) received a low-fiber diet alone for 6 mo. We found that diverticulosis occurred in 91.7% (11 of 12) of pigs in the CI + diet group and 100% (8 of 8) in CI-alone group. Moreover, around 30-75% of colon CI spots for each pig developed diverticular lesions. Diet alone for 6 mo 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 mo had no influence on the generation time or incidence rate of diverticulosis. In this model, digestion of the collagen in the colonic wall is sufficient to cause diverticulosis. NEW & NOTEWORTHY Effective large animal models of diverticulosis are currently lacking for the study of diverticular disease. This study marks the first time that a swine model of diverticulosis was developed by damaging colon wall structure, combined with or without a low-fiber diet. We found that a defect of colon wall could result in colon diverticular lesions within 6 mo in swine. This animal model mimicking the pathological process of diverticulosis is of great clinical value.

Keywords: animal model; collagenase; colon; diverticula; low-fiber diet.