The effect of a free-radical scavenger, N-2-mercaptopropionylglycine, on the survival of skin flaps.

Abstract

Oxygen free radicals may have an important role in tissue injury, which occurs on reperfusion of previously ischemic skin flaps. Therefore, therapy directed against the toxic effects of reactive oxygen species may protect skin flaps from ischemia/reperfusion injury. Various scavengers of oxygen free radicals have previously been reported to be effective in ameliorating ischemia/reperfusion injury. In the present study, N-2-mercaptopropionylglycine (MPG), a free-radical scavenger, was evaluated for its effectiveness in limiting the extent of necrosis resulting from ischemia/reperfusion injury in rat skin. Island skin flaps were elevated in the abdomen and groin based on an inferior epigastric neurovascular pedicle. The venous drainage from the flap was occluded for 7 hours, and reperfusion was established. The majority of flaps in the control group exhibited complete necrosis on Day 7 postoperatively. Treatment with systemic MPG (20 mg/kg of body weight) significantly improved flap survival from 22 to 71% (p less than 0.01) when administered at the time of reperfusion. However, MPG administered 1 hour after reperfusion did not influence the survival of the flaps. The results suggest that MPG may exert its beneficial effects on flap survival by scavenging oxygen free radicals formed at the time of reperfusion following prolonged ischemia.