Administration of bovine superoxide dismutase prevents sequelae of spinal cord ischemia in the rabbit.

The contribution of free radical-mediated reperfusion injury to the ischemic damage caused by total arterial occlusion has been investigated in a model of transient spinal cord ischemia in the rabbit. Spinal cord ischemia was produced in 20 anaesthetized rabbits by temporary luminal occlusion (20 min) of the abdominal aorta below the renal arteries. Superoxide dismutase (5 mg/kg) (10 animals) was infused before and during reperfusion below aortic occlusion using an infusion pump that infused the enzyme through the contralateral femoral artery. Control (10 animals) received sterile saline with the same procedure. In this later group, 4 animals developed paraplegia, 4 were paretic and only 2 were normal. However, in the treated group, 6 animals were normal while 3 were paretic and only one appeared paralyzed. We conclude that: a) oxygen free radicals generated during reperfusion are involved in producing the ischemic injury, and b) the ischemic spinal cord injury is prevented by superoxide dismutase.