REMOVING OXYGEN-DERIVED FREE-RADICALS STIMULATES HEALING OF ETHANOL-INDUCED EROSIVE GASTRITIS IN THE RAT

The effect of the radical removing agents, allopurinol and dimethyl sulphoxide (DMSO), on the healing rate of ethanol (1 ml of 40 % solution) induced gastric mucosal injury was studied in the rat. One millilitre of 1, 2 or 5 % allopurinol or DMSO were instilled into the stomach 1, 24 and 48 h after giving ethanol by gavage. One hour after administration of ethanol, gastric mucosal injury was produced in all animals (20.4 +/- 1.2 mm-2, mean +/- SEM, n = 10). Treatment for 24 h with 2 % allopurinol or DMSO significantly (p < 0.01) reduced the extent of the ethanol injury (11.1 +/- 0.8 and 11.9 +/- 0.9 mm-2, respectively, vs. 19.2 +/- 1.1 mm-2, n = 10) and this was similarly achieved by the 5 % solutions (10.4 +/- 0.9 and 10.2 +/- 0.8 mm-2, respectively, vs. 19.2 +/- 1.1 mm-2, n = 10). After treatment for 48 h, 30 % of animals having 1 % allopurinol or DMSO remained with injury significantly (p < 0.001) less than that seen with ethanol alone (4.1 +/- 0.4 and 3.9 +/- 0.5 mm-2, respectively, vs. 12.1 +/- 0.9 mm-2, n = 10); however, none treated with 2 or 5 % solutions remained with any injury. Healing of this injury was confirmed microscopically and was achieved by regeneration. Thus, removing oxygen-derived free radicals stimulates the healing of ethanol-induced acute gastric mucosal injury in the rat.