Carrageenan-induced intestinal injury in the rat--a model for inflammatory bowel disease.

The cause of inflammatory bowel disease (IBD) remains unknown. In this report, an attempt is made to produce a suitable animal model for studying the pathobiology of IBD, especially its pathogenesis. Sprague-Dawley rats were divided into four groups of six (A, B, C, D). The experimental design involved prior parenteral sensitization of groups A and B by a 1.5 percent solution of lambda degraded carrageenan followed by oral administration of the same solution for 30 days to groups A and C. The animals were then sacrificed, and the small intestine was evaluated for injury. Oral carrageenan caused significant intestinal injury as evidenced by ulceration, abnormal villous pattern, degree and extent of inflammation [p = 0.0001 for groups (A + C) versus (B + D)]. Prior sensitization aggravated the effects of oral carrageenan. Overall, the inflammation produced was reminiscent of human IBD in that there was pin-point ulceration, focality of lesions and lymphoid hyperplasia with microgranulomas. It was concluded that this carrageenan model may prove to be particularly useful for studying the pathobiology of human IBD.