神经干细胞移植防治骨骼肌失神经肌萎缩的电生理研究

目的探讨采用神经干细胞移植的方法防治骨骼肌失神经萎缩的可行性。方法采用机械分离的方法从孕14～16 d的SD孕鼠中获取神经干细胞,并于神经元限定性培养基中进行传代培养,制备神经干细胞单细胞悬液。采用切断右侧胫神经的方法建立腓肠肌失神经支配的动物(SD大鼠)模型。将108只SD大鼠按注射药物的不同随机分为3组,每组36只大鼠。实验组:将神经干细胞悬液注射到切断的胫神经远端。损伤组:注射等量的生理盐水。对照组:注射等量的细胞培养液。术后8、12周采用HRP逆行示踪技术检测失神经骨骼肌重获神经再支配的情况,并应用肌肉电生理方法对重获神经再支配的骨骼肌进行功能评价。结果术后8、12周实验组用电刺激细胞移植部位的腓肠肌,均可引出肌肉收缩活动;且随着时间的延长,单次收缩的波幅、速度,和强直收缩的时间和强直收缩波幅的恢复率均进一步得到改善。对照组和损伤组均未能引出肌肉活动。结论神经干细胞移植能够实现失神经骨骼肌的神经再支配,并且能够与骨骼肌建立起功能性突触连接,有效预防骨骼肌的萎缩。

Prevention of denervation muscle atrophy by transplantation of neural stem cells: an electrophysiological study

Objective To investigate the feasibility of preventing atrophy of denervated skeletal muscle by neural stem cell transplantation into peripheral nerve. Methods Neural stem cells were isolated from spinal cord of P15 day rats and cultured in a serum-free medium. Single cell suspension was obtained. Gastrocnemius muscle denervation model was set up by transecting right tibial nerve in 108 SD rats that were randomly divided into 3 groups with 36 in each. In the experimental group neural stem cells were injected into the distal stump of the tibial nerve. Same dose of normal saline and cell culture media was injected in the injury group and the control group respectively. At 8 and 12 weeks postoperatively, reinnervation of denervated skeletal muscle was determined by using horseradish peroxidase (HRP) retrograde tracing and electrophysiological examination. Results At 8 and 12 weeks postoperatively, contraction of the gastrocnemius muscle could be induced by electric stimulation in the experimental group but not in the injury and control groups. Force and velocity of twitch tension and force and duration of tetanic tension of the gastrocnemius muscle increased as postoperative interval prolonged. Conclusion Neural stem cells transplanted into the peripheral nerve can reinnervate denervated skeletal muscle and form neuromuscular junction to effectively prevent muscle atrophy.