多次缺血预处理对兔脊髓缺血性损伤时金属元素的影响

背景缺血预处理对主动脉手术的脊髓缺血性损害有良好的保护作用,但是脊髓缺血预处理保护作用的机制尚未完全阐明.目的探讨多次缺血预处理对兔脊髓缺血再灌注损伤的保护作用及其机制.设计以实验动物为研究对象,完全随机对照实验研究.单位一所大学医院的麻醉科.材料实验于2002-09/12在武汉大学人民医院麻醉学研究室完成.24只日本大白兔随机双盲分为假手术组、缺血再灌注组和缺血预处理保护组,每组8只.干预假手术组不阻断主动脉,缺血再灌注组阻断主动脉45 min,缺血预处理保护组阻断主动脉5 min,开放5 min,反复4次之后再阻断45 min.主要观察指标术后第7天检测脊髓组织金属元素(钙,镁,铜,锌)的浓度.术后观察后肢神经功能的评分、后肢针电极肌电图和脊髓组织病理学的改变.结果缺血再灌注组脊髓组织钙,铜的浓度较假手术组显著性升高(P＜0.05或0.01),镁,锌的浓度则显著性降低(P＜0.05).缺血再灌注组脊髓组织钙、锌的浓度分别较缺血预处理保护组显著性升高或降低(P＜0.01).缺血再灌注组后肢神经功能评分均显著性低于假手术组和缺血预处理保护组(P＜0.05或0.01),脊髓病理学和后肢肌电图亦较缺血预处理保护组有显著性病理改变(P＜0.01).结论多次缺血预处理对兔脊髓缺血再灌注损伤具有显著而又快速的保护作用,其保护机制与维持缺血区域钙,镁,铜,锌离子的平衡有关.

Influence of repetitive ischemic preconditioning on metal elements during ischemic injury of spinal cord in rabbits

BACKGROUND: It has been reported that the ischemia preconditioning (IPC) had credible protective efficiency on ischemic injury of the spinal cord during aorta operation, but the mechanism of the protective efficiency of IPC had not been clarified.OBJECTIVE: To study the protective effects of repetitive IPC on ischemic injury of spinal cord and its mechanism in rabbits.DESIGN: A completely randomized controlled study based on the experimental animals.SETTING: Department of anesthesiology in a university hospital.MATERIALS: The experiment was completed in the Department of Anesthesiology, Renmin Hospital, Wuhan University during September and December 2002. Twenty-four Japanese rabbits were randomly and double-blindly divided into sham-operation group, ischemia-reperfusion group and IPC group with 8 rabbits in each group.INTERVENTIONS: In sham-operation group, abdominal aorta was not clamped. Spinal cord ischemia was induced by infra-renal aortic cross-clamp for 45 minutes in ischemia-reperfusion group. Before the 45 minutes ischemia, the rabbits in the IPC group underwent four cycles of ischemia preconditioning, i.e. clamping abdominal aorta for 5 minutes then reperfusion for 5 minutes.MAIN OUTCOME MEASURES: The concentrations of calcium, magnesium, copper and zincum in spinal cord were measured in the 7th day after operation. Postoperative neurological function, EMG of rear limb, and spinal cord histopathological changes were assessed in all groups after operation.RESULTS: The concentrations of calcium and copper in spinal cord in ischemia-reperfusion group were significantly higher than those in sham-operation group( P ＜ 0. 05 or 0. 01 ), but magnesium and zincum significantly lower( P ＜ 0. 05). Compared with IPC group, calcium in ischemia-reperfusion group was significantly higher( P ＜ 0.01 ), but zincum significantly lower( P ＜ 0.01 ) . The neurological function and histopatholohical changes in ischemia-reperfusion group were much lower than those in sham-operation group and IPC group ( P ＜ 0.05 or P ＜ 0.01) . And there was significantly worse change of EMG in ischemia-repeffusion group than that in IPC group(P ＜ 0.01).CONCLUSION: Repetitive ischemic preconditioning can protect rabbit spinal cord from ischemia reperfusion injury quickly, and one possible reason for its protective effect is to maintain the balance of calcium, magnesium,copper and zincum in ischemic region.