Therapeutic effect of colloid bismuth subcitrate in experimental colitis in the rat

Colloid bismuth subcitrate (CBS) has a protective effect on ulcerated gastric and duodenal mucosa. To investigate its effect on large intestinal mucosal injury, we used acetic acid-induced colitis in the rat. Colitis was produced in male Wistarrats by rectal instillation of 1 nil of 10% acetic acid followed immediately by 1.5 ml of NaCl 0.9% (saline) enema. 1.5 ml of saline containing 240 mg of CBS or saline alone were then administered rectally every 24 h for 5 days. Another group of animals received CBS only. On the sixth day the distal colon was examined macroscopically and histologically using a 0 (nor mal) to 3 (necrosis) score. Prostaglandin E₂ (PGE₂) was measured by RIA (ng/mg protein). CBS significantly reduced both macroscopic and microscopic scores from 2.09 to 1.25 (p< 0.02) and from 2.4 to 1.08 (p<0.02) respectively. It also induced a significant reduction in PGE₂ from 1.6 to 0.57 (p < 0.004) in the inflamed colonic mucosa. The significant protective effect of topical CBS, which is accompanied by a reduction of PGE₂, indicates that CBS may have a role in the treatment of colitis.