BACKGROUND: It has been obtained by the animal experimental and clinical researches that electroacupuncture promotes the regeneration of peripheral nerve, but its mechanism is still unknown. Neurotrophic factor (NF) maintains the survival of neurons in injured nerve and promotes the axonal regeneration. The observation of the changes of nerve growth factor (NGF) before and after electroacupuncture stimulation probably provides a new approach on revealing peripheral nerve disorder.OBJECTIVE: To observe the effects of electroacupuncture on NGF in regeneration microenvironment after facial nerve injury.DESIGN: Complete randomized-division and controlled animal experiment.SETTING: Department of Acupuncture-Moxibustion of West China Hospital affiliated to Sichuan University.MATERIALS: The experiment was performed in Animal Experiment Center of West China Hospital affiliated to Sichuan University from September to December 2001, in which, 50 New Zealand healthy adult rabbits were employed and randomized into 2 groups, named experiment group and the control, 25 rabbits in each one.METHODS:① After intravenous anesthesia on experimental animal,the upper buccal branch of facial nerve was separated and exposed. Under surgical magnifying glass, the nerve was cut off and a silica-gel tube was used to be inlayed in two broken ends and fixed with stitching, by which, a regeneration chamber is formed. In experiment group, on the day when the rabbit was completely resuscitated from anesthesia in the operation, electroacupuncture was applied. Points: Yifeng (TE 17), Dicang (ST 4), Jiache (ST 6) and Hegu (LI 4). Method of treatment: perpendicular puncture was applied on Yifeng (TE 17), 1 cm deep; penetrating puncture was from Dicang (ST 4) to Jiache (ST 6), 1.5 cm deep; and on Hegu (LI 4), 0.5 cm deep. The electrodes was attached on Yifeng (TE 17) and Dicang (ST 4) respectively, with dense-disperse wave, at 18-20 Hz, 1.5 V. The needles were retained for 30 minutes and the treatment was given once a day, totally for 14 days.In the control,no any management was applied.② On the 3rd, 5th 7th, 10th and 14th days after surgery, 10 animals were sacrificed, 5 rabbits in each of experiment group and the control. The fluid was collected from the regeneration chamber and double antibodies sandwiched enzyme-linked immunosorbent assay (ELISA) was used to determine NGF level in regeneration chamber. ③ t test was adopted for the difference comparison of measurement data.MAIN OUTCOME MEASURES: Comparison of NGF level in regenerated chamber on the 3rd, 5th, 7th 10th and 14th days after surgery RESULTS: Fifty rabbits were all in result analysis. From the 3rd day to 7th day after surgery, NGF level in regeneration chamber was not different remarkably between experiment group and the control (P ＞ 0.05). On the 10th and 14th days, NGF level in regeneration chamber in experiment group was higher remarkably than that in the control [On the 10th day after surgery: (2 793.0±163.1), (2571.1±91.6) ng/L; on the 14th day after surgery: (2 696.1±147.5), (2 243.7±271.2) ng/L, t=4.45, 3.44, P ＜ 0.01].On the 7th day after surgery, NGF levels in regeneration chamber in both experiment group and the control were up to the peak. But, since the 14th day after surgery, NGF level in the control began declining, that in experiment group was still kept at a relatively high level.CONCLUSION: Electroacupuncture improves and maintains the stable high level of NGF in regeneration microenvironment after facial nerve injury, which is probably one of the mechanisms of electroacupuncture on promoting the regeneration of peripheral nerve.%背景:通过动物实验和临床研究,已获得了电针能促进周围神经再生的证据,但其机制尚没有明确的结论.神经营养因子可以维持损伤神经的神经元存活和促进轴突的再生,观察神经生长因子在电针刺激前后的变化,可能为揭示电针治疗周围神经病变提供新思路.目的:观察电针对面神经损伤后再生微环境中神经生长因子的影响.设计:完全随机分组设计,对照动物实验.单位:四川大学华西医院针灸科.材料:实验于2001-09/12在四川大学华西医院动物实验中心的实验室完成.选用成年健康的新西兰兔50只,随机分为2组:针刺组和对照组,每组25只.方法:①实验动物静脉麻醉后,分离暴露面神经上颊支,在手术放大镜下切断神经,用硅胶管将两断端嵌入并缝合固定,形成再生室.针刺组于术后当天麻醉完全醒后开始接受电针治疗,取穴:翳风,地仓,颊车,合谷.刺灸方法:翳风,直刺1 cm,地仓透颊车1.5 cm,合谷0.5 cm.电针两极分别置于翳风和地仓,选用疏密波,频率18～20 Hz,电压1.5 V,留针30 min,1次/d,干预14 d;对照组不作任何处理.②术后3,5,7,10,14 d分别处死10只动物,实验组与对照组各5只.抽取再生室内液体,采用双抗体夹心酶联免疫吸附法测定再生室内神经生长因子水平.③计量资料差异比较采用t检验.主要观察指标:术后3,5,7,10,14 d两组再生室内神经生长因子水平比较.结果:兔50只均进入结果分析.在术后3～7 d,实验组和对照组再生室内神经生长因子水平差异不明显(P＞0.05),术后10和14 d,实验组再生室内神经生长因子水平明显高于对照组[术后10 d:(2 793.0±163.1),(2 571.1±91.6)ng/L;术后14 d:(2 696.1±147.5),(2 243.7±271.2)ng/L,t=4.45,3.44,P＜0.01].术后第7天,实验组和对照组再生室内神经生长因子水平均达到峰值,但对照组在术后14 d开始降低,实验组仍保持在较高的水平.结论:电针对面神经损伤后再生微环境中神经生长因子水平有提高其水平和维持平稳水平不下降的作用,这可能是电针刺激促进周围神经再生机制的一方面.
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