The effect of free radical scavengers on outcome after infection in burned mice

Thermal injury generates free radicals from various cellular populations, and modulation of free radical activity with scavengers may improve outcome. Balb/c mice were infected with Ps. aeruginosa the day after burn injury and mortality rates observed. Tocopherol was given by gavage daily for 4 days starting 2 days before burn. Survival was improved in the groups receiving 25 and 250 IU/kg compared to control. In other groups, tocopherol was given after burn, but mortality rates were not changed. Treatment with the oxygen radical scavengers ascorbic acid, and a combination of superoxide dismutase and catalase had no effect on mortality. We conclude that ascorbic acid, superoxide dismutase, and catalase do not appear to benefit survival after thermal injury and infection in this murine model. Tocopherol given in high doses of at least 25 IU/kg by gavage preceding injury and continued thereafter for 2 days did improve survival, but this benefit was not seen if tocopherol was not started until after injury.