缺血预处理对兔主动脉阻断后脊髓一氧化氮、后肢神经功能和肌电图的影响

Effects of ischemic preconditioning on spinal cord nitric oxide,neurologic function and EMG of rear limb after abdominal aorta occlusion in rabbits

目的 探讨缺血预处理 (IPC)对缺血预处理对兔主动脉阻断后脊髓功能和一氧化氮(NO)的影响。方法 2 4只日本大白兔随机分为假手术组 (A组 )、缺血再灌注组 (B组 )和IPC保护组 (C组 ) ,每组 8只。分别于首次预处理即刻 (C 40 )、缺血即刻 (I0 )、缺血 45min(I45)、再灌注后 60min(R60 )和术后 7d处死动物前即刻 (R7d)采血检测血清和R7d脊髓组织NO的浓度。术后观察后肢神经功能的评分、后肢针电极肌电图 (EMG)和脊髓组织病理学的改变。结果 缺血再灌注损伤后B组血清NO浓度较缺血前和A、C组对应时点值显著升高 (P <0 .0 1)。C组R7d血清NO浓度明显低于其他时点及A组R7d测定值 (P <0 .0 5或 0 .0 1)。B组脊髓组织NO浓度显著高于A、C组(P <0 .0 1)。B组后肢神经功能和脊髓病理学评分均显著性低于A、C组 (P <0 .0 5或 0 .0 1) ,其后肢EMG亦较C组有显著性病理改变 (P <0 .0 1)。结论 IPC对家兔主动脉阻断后脊髓缺血再灌注损伤有良好的保护作用 ,其保护作用机制与抑制NO的生成有关。

Objective To study the effects of ischemic preconditioning (IPC) on spinal cord nitric oxide,neurologic function and EMG of rear limb after abdominal aorta occlusion in rabbits.Methods Twenty-four rabbits were divided into sham operated group (group A, n=8),ischemic and reperfusion group (group B, n=8) and IPC group (group C, n= 8).Spinal cord ischemia was induced by 45 min of infra-renal aortic occlusion.Four cycles of ischemic preconditioning,i.e.occluding abdominal aorta for 5 min,then reperfusing for 5 min,practised the IPC.The concentration of nitric oxide in serum was measured at the follow time points: the moment of first IPC (C -40) and ischemia (I 0),45 min after ischemia (I 45),60 min and 7th day after reperfusion (R 60 and R 7?d).The concentration of nitric oxide in spinal cord were also measured in R 7?d.Postoperative neurologic function and EMG of rear limb,and spinal cord histopathological changes were assessed in all groups.Results Compared with the time points before ischemia and the same points in group A or C,the concentration of nitric oxide in serum of group B was significantly increased (P< 0.01).In group C,the concentration of nitric oxide in serum of R 7?d was significantly decreased as compared with other points or R 7?d in group A (P< 0.05 or 0.01).The concentration of nitric oxide in spinal cord in group A was significantly different from that in group A or C (P< 0.01).Compared with group A or C,the neurologic function and histopatholohical changes were more serious in group B (P< 0.01).And there was significantly worse change of EMG in group B than in group C (P< 0.01).Conclusion Ischemic preconditioning can protect rabbit spinal cord from ischemic reperfusion injury,which was associated with the inhibition of the production of nitric oxide.