急性腰椎管狭窄动物模型的建立及对马尾神经动作电位的影响

Establishment of spinal canal stenosis in animal model and effect of action potential of Cauda Equina

目的通过高频率刺激和追加压迫,观察不同刺激条件和压力下受压马尾神经的复合动作电位(compound muscle action potential,CAMP)和复合感觉神经动作电位(compound sensory nerve action poten-tial,SNAP)的变化情况,探讨椎管狭窄导致马尾神经受压而引发的间歇性跛行的发病机制。方法 SD大鼠30只,分成5组,每组6只。对照组仅行单纯L5椎板切除;其他4个实验组将特制硅胶片插入L4及L6椎管,造成横截面分别积缩小30%的双节段狭窄。施加静态压迫2 h后,单纯压迫恒定组不施加动态负荷;单纯压迫增加组行追加压迫6 min;HFS压迫恒定组施加高频率刺激6 min;HFS压迫增加组施加高频率刺激同时追加压迫6min。负荷后,各组均恢复到原始静态受压状态继续检测30 min。结果静态压迫2 h,各实验组的CAMP和SNAP无明显变化(P<0.05)。动态负荷后,与对照组相比,单纯压迫恒定组动作电位无变化,而其他3组动作电位均发生下降,且HFS压迫增加组最为明显,30 min时,除HFS压迫增加组的CMAP未恢复至正常水平,其他各组均恢复至正常水平。结论动态负荷使急性受压马尾神经动作电位发生一过性降低。

【Objective】To investigate the effect of CAMP and SNAP of cauda equina under the different condition of dynamic burden（DB） and to clarify the mechanism of neurogenic intermittent claudication.【Methods】Thirty SD rats were divided into 5 groups（6 in each group）.The laminectomy of L5 was performed in control group.In the experimental groups,the silicon sheets were inserted into the spinal canal of L4and L6 to cause double level compression of cauda equina by 30%.Two hours after onset of compression,no dynamic burden was introduced in simple compression constant group.Only high frequency stimulation（HFS） was introduced for 6 minutes in HFS compression constant group.Both HFS and additional increased compression were introduced for 6 in HFS compression increase group.While only additional increased compression was introduced for 6 minutes simple compression increase group.After 6 minutes of dynamic burdens,all were returned to the status of static compression for another 30 minutes and then electrical examination was made.【Result】After 2h compression,there was no significant change in all groups.Under dynamic burden,there was no significant change in simple compression group,action potential in other three experimental groups decreased after introduction of DB.In 30min all changes recovered to the normal level except the CAMPs of HFS increase group.【Conclusion】DB can introduce action potential of cauda equnia transiently decrease.