缺血预处理对鼠后肢缺血再灌注下脊髓腰骶膨大运动神经元的保护作用

目的]对大鼠一侧后肢的缺血再灌注损伤行不同条件缺血预处理,观察脊髓腰骶膨大处运动神经元超微结构的变化,探讨其保护作用.方法]通过血管夹暂时阻断大鼠左侧髂总、髂内和髂外动脉,建立大鼠后肢缺血模型.以缺血6h再灌注2h和12 h分为A、B两组,预处理方式为缺血10 min血液复流10 min,按无预处理、预处理1次、无时间间隔预处理2、3次,分成A0、A1、A2、A3；B0、B1、B2、B3组.取材腰骶膨大处脊髓灰质前角,光镜及透射电镜下观察不同条件预处理对缺血再灌注损伤中脊髓前角超微结构变化.结果]组织形态观察结果显示A0组缺血再灌注损伤后神经元细胞减少,核溶解消失,损伤明显,预处理后神经元细胞增多,可见部分细胞核存在；B0组缺血再灌注损伤后神经元细胞大部分坏死溶解,预处理后坏死溶解现象减轻.超微结构观察显示A0和B0组脊髓前角神经兀细胞不同程度核周器扩张损伤,出现内质网扩张、大量线粒体空泡以及核膜溶解消失.预处理后损伤程度有所减轻,叠加预处理后损伤进一步减轻.结论]缺血预处理能减轻大鼠肢体缺血再灌注下脊髓腰骶膨大运动神经元的损伤,对脊髓具有保护作用.反复3次预处理产生的保护作用优于2次预处理及1次预处理.

Protective effects of ischemic preconditioning on motoneurons in rat lumbosacral enlargement following limb ischemia/reperfusion injury

Objective] To observe the protective effect of limb ischemic preconditioning on motoneurons in rat lumbosacral enlargement following limb ischemia/reperfusion injury.Method]The left hindlimb ischemia-reperfusion injury model of rats was performed by the temporary blocking of left common iliac artery,intenral iliac artery,external iliac artery and femoral artery together using artery clips.Rats were divided into group A and B according to the 2-hour and 12-hour reperfusion after 6-hour ischemia.Group A and B were subdivided into four sub-groups respectively(A0,A1,A2,A3 and B0,B1,B2,B3) which were based on no ischemic preconditioning,once preconditioning,twice preconditioning and three times preconditioning.Limb ischemia preconditioning was 10 minutes reperfusion after 10 minutes ischemia.The ultrastructural structures morphology of ventral horn in lumbosacral enlargement were assessed by light microscope and transmission electron microscope.Result]The histomorphologic changes were observed that there were obviously injury for decrease of neuronal cells and nuclears dissolved in the A0 group,while the neuronal cells were increasing and partial nuclears were the preconditioning.Most of neuronal cells were necrosis and dissolved in the B0 group,and the necrosis was less after the preconditioning.The ultrastructure showed that organelles around nuclear and endoplasmic reticulum were expansion,mitochondria appeared empty bubbles and most of nuclear membranes were dissolved in A0 and B0 group.The ischemia-reperfusion injury was less after preconditioning.The less injury,the more existence was found after preconditioning.Conclusion]There was protective effect of limb ischemic preconditioning on spinal cord following ischemia/reperfusion injury,which can reduce the injury of motoneurons in lumbosacral enlargement.The protective effect of three times ischemic preconditioning is better than the once and twice preconditioning.