The purpose of this study was to analyse the blocking effect of superoxide dismutase (S.O.D.) at doses of 15.000 U.I. per kilogram (body weight), on the release of oxygen-derived free radicals, experimentally caused in the rat by burning 20% of the surface of its body, and its impact over macroscopic and microscopic lesions of the gastric mucosa.

We used 48 rats divided into 5 groups. In groups 3 and 5 we provided S.O.D. i.v. immediately after the burn. All the animals had a catheter in their femoral vein for the administration of drugs.

Morphologic data showed that 2 hours after the burn S.O.D. did not have any influence on the gastric injury; 5 hours after the burn, the morphologic damage of the gastric mucosa was less severe. The scavenging of the superoxide ion (free radical) by the superoxide dismutase may be responsible of the lower tissular damage of the gastric mucosa.

These results confirm that a period of initial ischaemia may be an important etiopathogenic factor in severe lesions of the gastric mucosa after burns.