Fiberoptic colonoscopic study of experimental chemical colitis

Acute diffuse chemical colitis was produced in rats with a high degree of reproducibility by the intracolonic administration of 10% acetic acid. The evolution and progression of this colitis was followed by performing serial fiberoptic colonoscopy using a needlescope and biopsy. Hyperemia appeared at 10 hours and ulcerations appeared at 24 hours in acetic acid-treated animals. After 3 days, the ulcers were covered with a yellowish exudate. At 8 weeks there was endoscopic and histologic healing of the lesions. No changes occurred in the saline-treated animals. Concomitant topical applications of epsilon-aminocaproic acid protected against acetic acid-induced injury.