Experimental colitis studied by colonoscopy in the rat: effect of indomethacin.

Diffuse colitis was produced in rats by the intracolonic administration of 10% acetic acid. The course and evolution of this chemical colitis was followed by performing serial fiberoptic colonoscopy and biopsy. The effect of intrarectal indomethacin on the prostaglandin E content of the colonic mucosa and on the severity of colitis as judged by endoscopic and histologic criteria was evaluated. Intrarectal administration of indomethacin was associated with decreased severity of inflammation and decreased prostaglandin E2 content of the colonic mucosa. This model may be useful in evaluating other potential therapeutic agents.