伴发兔颈脊髓空洞的侧凸形成机制及BMSC移植干预的实验研究

Experimental research on the mechanism of scoliosis onset associated with rabbit cervical syringomyelia and the effect of scoliosis improvement after BMSC transplatation Abstract: With the widespread use of MRI, syringomyelia has been discovered with increasing frequency in patients with scoliosis. Craniocervical decompression and placement of syrinx drainage could not improve the neurological deficits effectively, moreover, the developmental trend of the scoliosis is subjective of debate after neurosurgical management. The dysfunction of the spinal cord around syrinx were considered as the main reason of unfavourable prognosis. The purpose of this study was to investigate the mechanism of scoliosis onset associated with cervical syringomyelia, and to explore the potential methods for assist biological therapy for syrinx with scoliosis, by using the first time constructed cervical noncommunicating syringomyelia model accompanied with thoracic scoliosis rabbits. 1) This study focused on early stage of syringomyelia and scoliosis in succession onset, comparing the differences of spinal bilateral sides though monitoring of motor and somatosensory evoked potentials, counting of motor nerve terminal branches, detecting of receptor expression level on neuromuscular conjunction, and observation of muscle fiber morphological abnormal, and exploring the hydrodynamics changes of the cerebrospinal fluid though fluid quantitative measurement of the cerebrospinal fluid flow, in order to analyze the interactive between syrinx and associated scoliosis during their occurrence and progress. 2) Then research involved the effect of the BDNF gene induced BMSC on the survival of the neurons and the regeneration of axons nearby the syringomyelia in vivo should be performed, though trasplantation of BDNF gene induced BMSC into syrinx cavity. The improvement of the function of spinal cord and the change of scoliotic curves should be observed. Moreover, we will investigate the expression of BDNF functional receptor and the downstream signal-transmitting passageways molecular, then explore the mechanism of BDNF gene induced BMSC on neurological deficits improvement and scoliosis improvement in noncommunicating syringomyelia model accompanied with thoracic scoliosis.

颈脊髓空洞多伴发脊柱侧凸，空洞周围的神经核团和传导束功能障碍严重影响其疗效。本项目为研究脊髓空洞伴发脊柱侧凸的发生机制，拟利用Kaolin诱导的非交通性颈脊髓空洞伴发侧凸兔模型，1) 针对空洞和侧凸相继发生的早期关键时相点，分别从脊髓神经元、感觉运动传导通路及脑脊液流体动力学的角度，重点关注脊髓结构和功能的不对称变化，关注脊髓张力变化，分析脊髓空洞与伴发的脊柱侧凸发生和演变间的相互影响；2) 采用基因克隆，RNA干扰及细胞移植等技术，将体外构建的BDNF基因正反两方面修饰的BMSC，移植入实验性脊髓空洞内，观察脊髓结构、功能变化及脊柱侧凸的转归，并检测BDNF功能性受体及其下游信号通路相关分子的表达变化，以确定BDNF转染BMSC对空洞周围神经元修复和轴突再生的影响，探讨其影响脊柱侧凸发展的作用机制；为临床外科治疗提供辅助生物学手段的进一步研究建立基础。

脊髓空洞常与脊柱侧凸相伴发，然而二者间存在何种联系目前尚不明晰。本研究基于kaolin诱导的伴发脊髓空洞脊柱侧凸兔模型，结合影像学、神经电生理学、分子生物学等手段对该模型中脊髓空洞与脊柱侧凸间的关系及脊柱侧凸发生的机制进行了探索，通过研究发现：1.脊柱侧凸的形成并非脊髓空洞形成后的继发性改变，应有更深层次的因素参与其中；2.脑脊液循环持续低流体动力学状态在脊柱侧凸的形成与进展过程中扮演重要角色：脑脊液循环持续低动力状态作为上游机制，作用于脊柱、脊髓导致不同病理结局：在脊柱导致脊柱侧凸的发生，在脊髓导致脊髓神经细胞凋亡和中央管内脑脊液蓄积而形成脊髓空洞；3.BDNF过表达基因慢病毒转染骨髓基质干细胞（BMSC）可通过激活神经营养因子信号转导通路，对脊髓神经细胞发挥保护和修复作用，抑制受损脊髓神经细胞凋亡；4.BDNF过表达基因慢病毒转染BMSC可能通过保护和修复受损脊髓神经细胞，而改善脑脊液循环并抑制脊柱侧凸发生。由此可见，探寻脑脊液循环状态改变在脊柱侧凸发生中的具体作用机制将对阐明脊柱侧凸的潜在发生机制具有重要意义；而基于此所开展的辅助生物学研究将为脊柱侧凸的预防及治疗提供新思路。