Carrageenan colitis in the guinea pig: pathological changes and the importance of ascorbic acid deficiency in disease induction.

In guinea pigs deprived of ascorbic acid, the oral administration of degraded E. spinosum carrageenan induced mild to moderate colitis, while E. cottonii consistently induced severe colitis. A variable degree of colitis was observed in scorbutic animals not receiving carrageenan. By contrast, in animals given large daily supplements of ascorbic acid, neither type of carrageenan consistently induced colitis and severe disease was rarely observed. The severe colitis induced by E. cottonii in scorbutic animals markedly affected the mid and distal colon and showed histological changes similar to human ulcerative colitis.