外源性表皮生长因子对大鼠坐骨神经损伤后感觉神经元超微结构变化的影响

目的应用外源性表皮生长因子(EGF)观察神经损伤后对背根神经节感觉神经元超微结构改变的影响。方法雄性SD大鼠18只，体重180～220g，随机分成对照组和EGF组，选用大鼠坐骨神经切断近端双重结扎的动物实验模型。对照组于神经结扎近端注入生理盐水5μl，EGF组注入hEGF5μl(10μgEGF溶于5μl生理盐水中)分别于手术后7、14、28d用4%多聚甲醛灌注后取腰5背根神经节观察感觉神经元超微结构的改变。结果腰5背根神经节超微结构均发生改变，随着时间的推移，对照组内感觉神经元细胞核逐渐缩小，核质淡，稀疏，线粒体肿胀，嵴消失，基质丢失，卫星细胞从与神经元紧密相连到与之分离。EGF组神经元仅出现线粒体轻度的变性改变，其余结构基本正常。结论EGF对神经损伤后感觉神经元有一定的保护作用

Exogenous EGF Effect on Change of Ultra-structure in Sensory Neuron Following Nerve Injury in Rat

Purpose　To observe exogenous epidermal growth factor (EGF) influence upon sensory neurons axotomy-induced and change ultra-structure of sensory.　Methods　Eighteen male Sprague-Dawely rats weighing 180-200 g(8-9 weeks of age)were randomly divided into two groups.One as control,the other was treated with EGF.Sciatic nerve injury model was set up by transecting left side sciatic nerve at 0.5 cm away from performed muscle.The proximal stump of sciatic nerve was ligated to inhibit nerve regeneration.Then 5 μl of normal saline in the control groups and an equal volume of EGF solution (containing 10 μg EGF) in the EGF treated groups were injected into the proximal of ligated nerve.The rats were sacrificed in 7,14,28 days of operative intervals respectively and transcardialy perfused with 4% para-fromaladehyde.The L5 dorsal root ganglion(DRG) were harvested.Eletromicroscope technique was used to observe the changes of L5 DRG sensory neurons axotomy-induced.　Results　A series of changes happened in the control group.The size of the nucles decreased.Nucleoplasm was scattered.The nucleolus was pale.Edema,loss of crest and matrix was found in the mitochondria. Satellite cells detached from the soma.The ultrastructure of L5 DRG sensory neurons in EGF groups get near to normal following nerve injury.　Conclusions　EGF could protect sensory neurons.