Limiting impairment of muscle function following ischemia and reperfusion in rabbits

Reperfusion injury is a phenomenon complicating microvascular reconstruction. Extensive investigations of free-radical scavengers exist in the literature. The potential beneficial effects of verapamil, deferoxamine, and dimethylsulfoxide were studied in the rabbit forelimb subjected to 3 hr of tourniquet ischemia, followed by a period of reperfusion. Five minutes prior to tourniquet release, rabbits were given single intravenous infusions of normal saline, verapamil (0.2 mg/kg), deferoxamine (50 mg/kg), or dimethylsulfoxide (100 mg/kg). Following reperfusion, neither light microscopy nor laser Doppler flowmetry revealed significant differences between the sham and treated limbs. Muscle function was evaluated by measuring maximal twitch tensions in the flexor digitorum superficialis. Deterioration of muscle contractile function at 0.5, 3, and 24 hr after reperfusion was significantly improved by treatment with verapamil or deferoxamine. Conversely, dimethylsulfoxide worsened muscle function post ischemia. Dimethylsulfoxide does not appear to be beneficial, while verapamil and deferoxamine may be of benefit in mitigating reperfusion injury in microvascular transplantation.