ATP敏感性钾通道参与兔脊髓缺血预处理的保护作用

ATP sensitive potassium channels are involved in the protective effect of ischemic preconditioning on spinal cord in rabbits

目的 探讨ATP敏感性钾通道是否参与兔脊髓缺血预处理的保护作用。方法 2 7只♂新西兰大白兔随机分成3组 (n =9) :即缺血组 (IC组 )、缺血预处理组 (IPC组 )及格列本脲 (glibenclamide ,ATP敏感性钾通道阻断剂 ) +缺血预处理组 (G +I组 )。IC组夹闭兔腹主动脉肾下段 2 0min ,复制兔脊髓缺血模型 ;IPC组预先使脊髓缺血 6min ,3 0min后再次阻闭兔腹主动脉肾下段 2 0min ;G +I组在缺血预处理前 2 0min静脉给予格列本脲 2mg·kg- 1,其他处理同IPC组。再灌注后 8、12、2 4和 48h分别对动物神经功能评分 ;再灌注 48h后 ,处死动物取脊髓 (L5～ 7) ,制作标本行组织病理学观察。结果 IPC组神经功能评分各时间点均高于IC组及G +I组 (P <0 0 5) ;与IC组及G +I组相比 ,IPC组脊髓前角正常神经细胞数明显增多 (P <0 0 1) ;IC组与G +I组在各时间点的神经功能评分及脊髓前角正常神经细胞数差异都无显著性 (P >0 0 5)。结论 兔脊髓缺血预处理的保护作用与ATP敏感性钾通道密切相关。

AIM To investigate whether ATP sensitive pota ss ium channels are involved in the protective effects of ischemic preconditioning on spinal cord in rabbits. METHODS Twenty seven male New Zealands white rabbits were randomly assigned to 3 groups (9 in each group):ischemia gro up(IC)、ischemic preconditioning group (IPC) and glibenclamide + ischemic precon ditioning group(G+I). In IC group, spinal cord ischemia was induced by an infrar enal aorta clamping for 20 min; IPC group underwent a 6 min ischemic preconditio ning followed by 30 min of reperfusion before the 20 min clamping; G+I group wer e administered glibenclamide (an ATP sensitive potassium channel blocker, 2 mg· kg -1 )intravenously 20 min before the ischemic preconditioning. Neurologic function was scored at 8,12,24 and 48 h after reperfusion. All animals were sa crificed at 48 h after reperfusion and the spinal cords (L 5～7 ) were remov ed for histopathologic study. RESULTS The neurologic function sco res in IPC group at each observe interval were higher than those in IC group and G+I group (P<0 05). Compared to IC group and G+I group, there were more no rmal neurons in anterior horn of spinal cord in IPC group 48 h after reperfusion (P<0 01). The neurologic function scores at each observe interval and the number of normal neurons in anterior horn of spinal cord between IC group and G +I group have no statistical differences. CONCLUSION The protecti ve effects of ischemic preconditioning on spinal cord in rabbits may be related to ATP sensitive potassium channels.