面神经异常传导通路形成的机制研究:交感神经重构参与异常肌反应形成

Hemifacial spasm (HFS) is a common clinical disorder characterized by paroxysms of involuntary contractions of unilateral facial muscles. Although the disease is not life threatering, the patient suffers from the attacks awfully due to physical discomfort and embarrassment. Although a high cure rate has been achieved by means of the microvascular decompression (MVD) surgery, the pathophysiology of the disorder remains unclear. Abnormal muscle response (AMR) to the electrical stimulation of a branch of facial nerve is a specific electrophysiological feature of primary HFS, The phenomenon of AMR means there’s some abnormal pathway between facial nerve fibers. Our study demonstrated that removal of the superior cervical ganglion in AMR-positive rat and then AMR disappeared, but drip of norepinephrine following removal of the offending artery, AMR waves were monitored again. We believe that the sympathetic nervous system in adventitia of the offending artery may contribute to the abnormal pathway between facial nerve fibers, but the mechanism is still unknown. Until recently, Sympathetic remodeling and electrical remodeling influence smutually, which become s an important factor of malignant arrhythmia and sudden death after myocardial infarction. Therefore, we hypothesize that up-regulation expression of nerve growth factor following the injury of sympathetic nervous system in the wall of the offending artery, promote the growth of sympathetic neuraxon, which triggers the sympathetic nerve remodeling and finally promotes the formation of abnormal pathway between facial nerve fibers. This study was undertaken to test the hypothesis based on a rat model of HFS by performing transmission electron microscopy, enhancement of NGF, inhabition of NGF, real time PCR, etc. Our study will provide novel insights into HFS treatment.

面肌痉挛（HFS）是一种常见的颅神经疾病，严重影响生活质量，微血管减压手术有着很好的疗效，但术后复发、无效等临床问题仍旧无法满意解决。异常肌反应（AMR）是HFS特征性的电生理波形，提示面神经纤维之间异常传导通路的存在。我们研究发现，阻断颈上交感神经节可以使已经存在AMR波形消失，而滴加肾上腺素可以使消失的AMR波形再次出现，因此我们认为交感神经系统在HFS异常传导通路形成中起着重要作用，但其上游形成机制尚不清楚。现有研究显示，交感神经重构引发的电重构是心律失常异常电传导基础。因此我们提出假说，责任血管外膜交感神经损伤后，通过上调神经生长因子表达，促进交感神经轴突的再生，启动交感神经重构过程，促进面神经各纤维之间异常传导通路形成。本研究将采用Moller的HFS模型，运用药物增强、交感抑制、透射电镜等技术，来验证这一假说，明确交感神经重构在AMR形成中的作用，为HFS的临床治疗提供新思路。

面肌痉挛是最为常见的颅神经疾病，微血管减压手术是治疗面肌痉挛最为有效的外科手段，已经在全世界广泛推广应用。异常肌反应作为一种特殊的神经电生理监测手段，提示面神经纤维之间异常传导通路的存在，是面肌痉挛特征性的电生理波形，广泛应用在面肌痉挛的诊疗过程中，包括：面肌痉挛的诊断及鉴别、微血管减压手术的责任血管判定、手术进程的控制、手术疗效的预测、术后无效及复发的判定、再手术方案的制定等等方面，起着不可替代的作用。但是异常肌反应的发生机理，目前尚不清楚，我们此次研究的目的即是深入探究AMR的发生机制。.我们研究发现，阻断颈上交感神经节可以使已经存在AMR波形消失，而滴加肾上腺素可以使消失的AMR波形再次出现，因此我们认为交感神经系统在HFS异常传导通路形成中起着重要作用，但其上游形成机制尚不清楚。现有研究显示，交感神经重构引发的电重构是心律失常异常电传导基础。因此我们将责任血管外膜交感神经损伤后，通过上调神经生长因子表达，促进交感神经轴突的再生，启动交感神经重构过程，促进面神经各纤维之间异常传导通路形成。我么通过不同时间点的电生理学监测、神经电镜等证实了交感神经重构的存在。.同时我们也将研究成果应用于临床，通过对AMR波形持续存在的患者进行面神经梳理，梳理后患者AMR波形消失，术后患者面部抽动症状缓解，这在临床应用方面证实了交感神经重构在AMR形成中扮演的作用，神经梳理可能打断了交感神经重构，打断了面神经之间的异常传导，进而改善了面肌痉挛患者的预后，提高了微血管减压手术的整体有效率，同时也为面神经梳理术治疗AMR持续存在的面肌痉挛患者提供依据。