RESUMEN
This work studied the involvement of free radicals in pathogenesis of different types of induced ulcer and the protective effect of some antioxidants. Some of the possible protective mechanisms of antioxidants [zinc sulfate, sodium selenite, N-acetylcysteine and vitamin E] were investigated against ethanol, indomethacin and across induced ulcer in rats. A group of six normal rats served as a control group. It was concluded that antioxidants zinc sulfate, sodium selenite, N-acetylcysteine and vitamin E can protect gastric mucosa against ethanol, indomethacin and stress induced ulcer in rats. The protective effect against gastric mucosal damage may be done through inhibition of lipid peroxidation of the cell membrane in association with hydroxyl radical scavenging activity, prevention of glutathione depletion, improvement of antioxidant capacity or preservation of NOS activity