ADDITIVE EFFECT OF ALLOPURINOL AND DEFEROXAMINE IN THE PREVENTION OF SPINAL-CORD INJURY CAUSED BY AORTIC CROSS-CLAMPING

Fourteen domestic swine were divided into two groups. Group A (n=7) wa s the control group, in which no pharmacologic intervention was applie d. In group B (n=7), the ischemic-reperfused spinal cord was treated w ith the combination of allopurinol (50 mg/kg/day for 3 days before the day of operation) and deferoxamine (Desferal, 50 mg/kg administered i ntravenously over 3 to 4 hours). The administration of deferoxamine wa s completed 1 hour before crossclamping. The crossclamp was placed on the descending aorta just distal to the left subclavian artery for 30 minutes. Proximal hypertension was controlled with sodium nitroprussid e and volume depletion. Methods of assessment included an evaluation o f the neurologic status of the animals by quantitative Tarlov criteria , blood flow by radiolabeled microspheres,and histologic examination o f the spinal cord. All animals in the control group, group A, were com pletely paraplegic with O% recovery by Tarlov criteria at 24 hours aft er the removal of the crossclamp. In contrast, all animals in group B, in which the combination of allopurinol and deferoxamine was used, co mpletely recovered (100% recovery by Tarlov criteria), and at 24 hours after the ischemic episode they were able to walk with no difficulty and had intact sensation. Functional parameters of these animals fully correlated with the morphologic findings. Widespread acute neuronal i njury and vacuolation of neuropil were observed in the control group o f animals. In contrast, animals in group B showed much less pronounced morphologic changes after the same period of ischemia. In summary, th e combined use of these agents significantly (p<0.001) reduced the inc idence of paraplegia induced by aortic crossclamping with 82% additivi ty.