Li Rong, Huang Zu-Cheng, Cui Hong-Yan, Huang Zhi-Ping, Liu Jun-Hao, Zhu Qing-An, Hu Yong
Institute of Biomedical Engineering, Chinese Academy of Medical Sciences and Peking Union Medical College, Tianjin; Department of Orthopedics and Traumatology, The Hong Kong University Shenzhen Hospital, Shenzhen, Guangdong Province, China.
Department of Spine Surgery, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong Province, China.
Neural Regen Res. 2021 Jul;16(7):1323-1330. doi: 10.4103/1673-5374.301486.
Fine motor skills are thought to rely on the integrity of ascending sensory pathways in the spinal dorsal column as well as descending motor pathways that have a neocortical origin. However, the neurophysiological processes underlying communication between the somatosensory and motor pathways that regulate fine motor skills during spontaneous recovery after spinal cord contusion injury remain unclear. Here, we established a rat model of cervical hemicontusive injury using C5 laminectomy followed by contusional displacement of 1.2 mm (mild injury) or 2.0 mm (severe injury) to the C5 spinal cord. Electrophysiological recordings were performed on the brachial muscles up to 12 weeks after injury to investigate the mechanisms by which spinal cord pathways participate in motor function. After spinal cord contusion injury, the amplitudes of somatosensory and motor-evoked potentials were reduced, and the latencies were increased. The forelimb open field locomotion test, grooming test, rearing test and Montoya staircase test revealed improvement in functions. With increasing time after injury, the amplitudes of somatosensory and motor-evoked potentials in rats with mild spinal cord injury increased gradually, and the latencies gradually shortened. In comparison, the recovery times of somatosensory and motor-evoked potential amplitudes and latencies were longer, and the recovery of motor function was delayed in rats with severe spinal cord injury. Correlation analysis revealed that somatosensory-evoked potential and motor-evoked potential parameters were correlated with gross and fine motor function in rats with mild spinal cord contusion injury. In contrast, only somatosensory-evoked potential amplitude was correlated with fine motor skills in rats with severe spinal cord injury. Our results show that changes in both somatosensory and motor-evoked potentials can reflect the changes in gross and fine motor functions after mild spinal cord contusion injury, and that the change in somatosensory-evoked potential amplitude can also reflect the change in fine motor function after severe spinal cord contusion injury. This study was approved by the Animal Ethics Committee of Nanfang Hospital, Southern Medical University, China (approval No. NFYY-2017-67) on June 11, 2017.
精细运动技能被认为依赖于脊髓背柱中上行感觉通路以及起源于新皮质的下行运动通路的完整性。然而,脊髓挫伤性损伤后自发恢复过程中,调节精细运动技能的体感和运动通路之间通信的神经生理过程仍不清楚。在此,我们建立了一个大鼠颈半侧挫伤性损伤模型,采用C5椎板切除术,然后对C5脊髓进行1.2毫米(轻度损伤)或2.0毫米(重度损伤)的挫伤性移位。在损伤后长达12周对肱部肌肉进行电生理记录,以研究脊髓通路参与运动功能的机制。脊髓挫伤性损伤后,体感和运动诱发电位的幅度降低,潜伏期延长。前肢旷场运动试验、梳理试验、竖尾试验和蒙托亚阶梯试验显示功能有所改善。随着损伤后时间的增加,轻度脊髓损伤大鼠的体感和运动诱发电位幅度逐渐增加,潜伏期逐渐缩短。相比之下,重度脊髓损伤大鼠的体感和运动诱发电位幅度及潜伏期的恢复时间更长,运动功能的恢复延迟。相关性分析显示,轻度脊髓挫伤性损伤大鼠的体感诱发电位和运动诱发电位参数与总体和精细运动功能相关。相比之下,重度脊髓损伤大鼠中只有体感诱发电位幅度与精细运动技能相关。我们的结果表明,体感和运动诱发电位的变化均可反映轻度脊髓挫伤性损伤后总体和精细运动功能的变化,体感诱发电位幅度的变化也可反映重度脊髓挫伤性损伤后精细运动功能的变化。本研究于2017年6月11日获得中国南方医科大学南方医院动物伦理委员会批准(批准号:NFYY - 2017 - 67)。