Protective effect of hyperoxic solution preconditioning on spinal cord ischemic injury in rabbits and its mechanism

    SANG Hanª²Fei1, ZHANG Yingª²Min2, XU Liª²Xian3, CHENG Hong4, GONG Gu2, MEI Qiª²Bing1, XIONG Liª²Ze2

    1Department of Pharmacology, 4Department of Pathology, School of Basic Medicine, 2Department of Anesthesiology, Xijing

    Hospital, 3Department of Anesthesiology, Stomatological College, Fourth Military Medical University, Xi¬ðan 710033, China

    ¡¾Abstract¡¿ AIM: To investigate whether hyperoxic solutioin preconditioning has protective effect on spinal cord ischemic injury in rabbits and whether oxygen free radicals are involved in the protective effect. METHODS: Thirtyª²two male New Zealands rabbits were randomly assigned to 4 groups (8 in each group): Control group (C ), hyperoxic solution preconditioning (H), dimethylthiourea (DMTU, free radicals scavenger) + hyperoxic solution preconditioning group (D+H) and DMTU group (D). In H group, hyperoxic solution 10 ml¡¤kg-1 was infused intravenously at a rate of 30 ml¡¤kg-1¡¤ h-1 every day for 5 days; In the same way, C group were administred the same volume normal saline instead of hyperoxic solution; D+H group were treated the same as H group except for administering 500 mg¡¤kg-1 DMTU intravenously 1h before each hyperoxic solution preconditioning; D group were administered 500 mg¡¤kg-1 DMTU intravenously once a day for 5 days. 24 h after last preconditioning, the spinal cord ischemia was induced for 20 min by infrarenal aortic occlusion. Neurologic status was scored at 48 h after reperfusion. Then, all animals were sacrificed and the spinal cords (L5ª²7) were removed for histopathologic study. RESULTS: The neurologic function scores and the number of normal neurons of anterior horn of spinal cord were significantly greater in H group than in C group, D+H group and D group (P<0.05), which had no statistical differences between C group¡¢D+H group and D group (P>0.05); There was a stong correlation between the neurologic function scores and the number of normal neurons in anterior horn of spinal cord (r=0.804, P<0.01). CONCLUSION: Hyperoxic solutioin preconditioning has a significant protective effect on spinal cord ischemic injury in rabbits and oxygen free radicals may be involved in the protective effect. ......