失神经支配红白肌肉早期运动神经营养活性研究

目的了解失神经支配后红白肌肉内脑源性神经营养因子(brain-derived neurotrophic factor,BDNF)早期含量变化及相应运动神经传导功能恢复情况,探讨靶器官对损伤运动神经再生修复的作用. 方法 Wistar大鼠40只,平均分为5组,其中1组为对照,其余4组剪断双下肢坐骨神经制作肌肉失神经支配模型,分别于神经损伤后1、3、7和14天采用免疫组织化学方法检测肌肉内BDNF含量.另取15只Wistar大鼠,钳夹双下肢坐骨神经制作失神经支配肌肉神经再生模型,于伤后7天和14天采用神经电生理方法测定神经传导速度及肌电图. 结果比目鱼肌(soleus,SOL)失神经支配后1、3和7天BDNF含量较对照组大幅度升高,差异有统计学意义(P＜0.01),但随时间推移呈下降趋势,14天BDNF含量与对照组接近(P＞0.05);腓肠肌(gastrocnemius,GAS)失神经支配后1、3、7和14天BDNF含量与对照组均接近(P＞0.05).失神经支配肌肉神经再生模型中,伤后7天失神经支配SOL和GAS均未测到动作电位;伤后14天支配GAS和SOL的运动神经传导速度分别恢复至正常值的(36.60±7.40)%和(42.50±3.50)%,二者差异无统计学意义(P＞0.05);GAS M波波幅恢复至正常值的(19.9±6.4)%,而SOL M波波幅恢复至正常值的(13.7±4.0)%,二者差异无统计学意义(P＞0.05). 结论失神经支配红、白肌肉内早期运动神经营养因子含量在不同时间内发生不同的变化,但支配两种靶器官的损伤运动神经功能恢复相近.失神经支配后靶器官的运动神经营养活性是其内部各种运动神经营养因子综合作用的结果.

STUDY ON EARLY MOTOR NEUROTROPHISM OF DENERVATED RED AND WHITE MUSCLES

OBJECTIVE: To investigate the early change of brain-derived neurotrophic factor (BDNF) in denervated red and white muscles and the regeneration of nerves innervating the muscles and to discuss the effect of the target organs on regeneration of the injured nerves. METHODS: Forty Wistar rats were divided into 5 groups. The sciatic nerves in 4 groups were sheared to make the models of the denervated muscles and the other one as control group. The amount of BDNF in muscles was measured with immunohistochemistry 1 day, 3 days, 7 days and 14 days after injury. The models of the regeneration of the nerves were made in another 15 rats whose sciatic nerves were disconnected with forceps. The nerve conduction velocity and electromyogram were tested with neuroelectrophysiology 7 days and 14 days after injury. RESULTS: The expression of BDNF in soleus increased significantly on the 1st day, the 3rd day and the 7th day (P<0.01); the expression in gastrocnemius was lower, but there was no significant difference (P>0.05) on the 1st day, the 3rd day, the 7th day and the 14th day when compared with control group. After 14 days of injury in the nerves innervating GAS and SOL, the nerve conduction velocities and the amplitudes of wave M recovered to (36.60+/-7.40)% and (19.9+/-6.4)% of normal value, and (42.50+/-3.50)% and (13.7+/-4.0)% of normal value respectively; there were no significant differences between the two muscles (P>0.05). CONCLUSION: There is difference in BDNF amount between the denervated red and white muscles, but the recovery of the two kinds of the motor nerves is similar, and the neurotrophism of denervated muscles was determined by all kinds of neurotrophic factors.