神经元中继器策略修复脊髓损伤的研究进展

Research progress of neuronal relay strategies in repairing spinal cord injuries

当成年哺乳动物发生严重的脊髓损伤后,皮质脊髓束等下行神经纤维(轴突)很难长距离跨越损伤区再生,导致损伤区以下的瘫痪肢体的运动功能难以恢复.从开始在脊髓损伤处移植胚胎源性神经组织起至今近30年,神经元中继器(neuronal relay)修复脊髓损伤的理念逐渐成为共识并得到进一步论证.国内外研究团队相继提出中继器的修复策略,即应用细胞因子、生物材料和干细胞等组织工程新技术,在改善受损伤脊髓组织微环境的同时提供内源或外源性神经元中继器(如神经网络组织或类脊髓组织),接收上、下行神经信息,并将神经信息传递给损伤区两端的脊髓固有神经元.神经元中继器修复脊髓损伤改变了“成年哺乳动物脊髓内上、下行轴突必须再生穿越全横断脊髓损伤区才能恢复脊髓运动和感觉功能”的传统理念.本文重点介绍了目前在神经元中继器修复脊髓损伤策略的指引下,利用再生医学交叉学科的新技术,恢复严重脊髓损伤后瘫痪肢体运动和感觉功能的研究进展.

In the event of a severe spinal cord injury(SCI)in adult mammals,the descending nerve fibers(axons),such as those in the corticospinal tract,are extremely difficult to regenerate over long distances across the injury area.Thus,the recovery of the motor function of paralyzed limbs below the damaged area of the spinal cord is problematic.For nearly three decades,beginning with the transplantation of embryonic nervous tissue into the SCI site,the idea of a neuronal relay to repair SCIs has been gradually recognized and further demonstrated.Research teams in China and abroad have successively proposed strategies of neuronal relays for the repair of SCIs.Some novel tissue engineering techniques,such as cytokines,biomaterials,and stem cells,have been used to provide an endogenous or exogenous neuronal relay(such as neural network tissue or spinal cord-like tissue)in an effort to improve the microenvironment of the injured spinal cord tissue.The neuronal relay receives the descending and ascending neural information and then transmits it to the intrinsic neurons in the rostral and caudal areas of the SCI area.The repair of SCIs by neuronal relay has challenged the traditional view that the ascending and descending axons must regenerate across the whole transection of the SCI area to restore spinal motor and sensory function in the adult mammalian spinal cord.Under the guidance of the idea of repairing SCIs with a neuronal relay,this review emphatically introduces current research progress in the recovery of motor and sensory function of paralyzed limbs after severe SCI with the new interdisciplinary technology of regenerative medicine.