局部应用GDNF对运动神经的保护作用研究

目的研究周围神经损伤后,经蛛网膜下腔置管局部应用外源性胶质细胞源性神经营养因子（glial cellline-derived neurotrophic factor,GDNF）对脊髓前角运动神经元的保护作用。方法成年SD大鼠随机分为两组,即手术加生理盐水组和手术加GDNF组。切断大鼠坐骨神经致相应脊髓前角运动神经元损伤,于L5、6腰椎椎间隙行蛛网膜下腔置管,并注入外源性GDNF（10μg/mL）,分别与术后4、8、12周行神经功能指数检测;于不同时间处死动物并取材,对L4～6节段脊髓标本冰冻切片,行尼氏体染色、光镜检查,并于术后12周取坐骨神经,行电镜检查并采用图象分析仪检测有髓神经纤维数目、髓鞘厚度和轴突直径。结果GDNF组的坐骨神经功能指数、脊髓前角运动神经元的存活率、有髓神经纤维数目、髓鞘厚度和轴突直径均优于对照组,经统计学处理,两组差异有显著性（P〈0.05）。结论通过蛛网膜下腔注入外源性GDNF保护相应的脊髓运动神经元的同时也促进外周神经功能的恢复。

Protective Effect of Glial Cell Line-Derived Neurotrophic Factor Infused into Cavitas Subarachnoidealis on Spinal Front Corner Motor Neurons

Objective To investigate the effect of exogenous glial cell line-derived neurotrophic factor（GDNF） infused into the cavitas suharachnoidealis on spinal front corner motor neurons after sciatic nerve axotomy. Methods Forty eight healthy SD rats were randomly divided into 2 groups ：NS group and GDNF group. The left sciatic nerve in rats were cut off. And then 0.9% saline and GDNF solution were injected into cavitas suharachnoidealis at L4-6 in NS group and GDNF group,respectively. The rats were sacrificed on postoperative day 4w,8w and 12w respectively. Their specimen of L4-6 spinal cord were taken at different time and sectioned. The Nissl staining in motor neurons were used for counting of motor neurons. Electron microscopic observation and morphometric analysis were performed at 12 weeks after operation. Results In GDNF group the number of motor neurons in spinal front corner higher than that of NS group. The mean axon diameters and mean myeline sheath thickness were significantly better in GDNF group than control group. SFI in GDNF group was lower in NS group. Conclusion The exogenous GDNF infused into the cavitas suharachnoidealis are supposed to protect the degenerated spinal motor neuron from death after sciatic nerve injury ,and to encourage the periphery nerve recovery.