大鼠脊髓损伤后感觉、运动及电生理变化

在应用磁控机械夹断法复制的大鼠脊髓损伤模型上,动态地观察了脊髓损伤后的感觉及运动机能变化,并进行了电生理学研究。结果表明,0.3A电流未能导致永久性瘫痪。术后2周,后肢的感觉及运动功能逐渐恢复;可记录到体感诱发电位(SEP)。0.4,0.5和0.8A电流均能导致大鼠永久性瘫痪;倾斜板及开阔场地行走分数均显著低于0.3A组;术后4周这些大鼠可产生行走样动作,于损伤部位再次切断脊髓后仍能出现这些动作;0.4A组可记录到早期SEP,再次切断脊髓后SEP消失。结果提示:(1)脊髓不全横断后,由于残留纤维活动,可在相当程度上导致大鼠感觉和运动机能的恢复;(2)脊髓完全横断后,后肢的上行冲动可能经再生的神经纤维向中枢端传导至脑;(3)大鼠脊髓内可能存在行走中枢模式发生器(CPG),适当刺激可激发其活动,并产生行走样运动。

SENSORY, MOTOR AND ELECTROPHYSIOLOGICAL CHANGES FOLLOWING PINCHING DAMAGE TO THE SPINAL CORD IN THE RAT

Sensory, motor and electrophysiological changes were dynamically observed on a spinal cord injury model produced by method of electromagnet-controlled pinching. No permanent paraplegia was seen in the group injured by current of 0.3A. Motor and sensory functions of the animal's hindlimbs recovered gradually and somatosensory evoked potential (SEP) of all animals in this group could be recorded two weeks after the injury.Permanent paraplegia, however, occurred in groups of 0.4A, 0.5A and 0.8A. IP (inclined plane) and open field walking (OFW) scores in these groups were significantly lower than those in the 0.3A group. All these animals displayed locomotion-like movement 4 weeks after the injury and even after complete retransection of their spinal cord. An early SEP could be recorded in the 0.4A group, but disappeared after retransection.The results indicate that: 1) the motor and sensory functions are able to recover considerably due to the spared nerve fiber activities when the spinal cord is not completely transected; 2) inputs from the hindlimbs may ascend to the brain probably through the regenerated nerve fibers after complete transection of the cord; 3) a kind of locomotion central pattern generator (CPG) might exist in the rat spinal cord and can be activated by adequate stimuli, causing locomotion-like movement.