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

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。

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

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.