面神经核内塑形变化在面瘫后遗症发生中的作用

OBSERVATION OF THE ROLE OF FACIAL NUCLEUS REMODELING IN THE GENESIS OF POST-PALSY SEQUELA

目的观察外伤性面瘫后,面神经核内运动神经元的定位分布与轴索再生变化,探讨其在面瘫后遗症联带发生中的作用。方法大鼠32只,面神经断伤吻合建立面瘫模型,采用尼氏染色与神经逆行荧光示踪技术,观察面瘫60d后健患两侧面神经核内运动神经元的定位分布与轴索再生变化,用透射电镜技术观察面瘫后90d时面神经核内运动神经元的超微结构改变。结果1.面瘫后健患两侧尼氏染色神经元的数量及分布特征基本一致,仅有神经元分布区域的缩小趋势,尼氏染色与超微观察均未发现面神经核内运动神经元有坏死与凋亡样改变。但患侧代表轴索成功再生的荧光金(FG)标记神经元数目较健侧明显减少(P<0.05),提示核内存在未被FG逆行标记但被尼氏染色的未达靶神经元。2.面神经颞支与颊支的荧光红(FR)与FG逆行示踪发现,面神经核颊支支配区内错位分布支配颞支的神经元,患侧的错位神经元比例较健侧增加(P<0.05)。同时,患侧面神经核内还出现代表轴索芽生,同时支配颞颊支的荧光双标神经元。结论外伤性面瘫后面神经核内的塑形中,除轴索芽生与迷向再生影响瘫后功能恢复外,核内还存在未成功再生的面运动神经元,其在面瘫后遗症联带发生中的作用也值得深入研究。

Objective To observe the remodeling process of reinnervation and somatotopy of facial motor neurons after traumatic facial paralysis, and then explore its role in the mechanism of post-palsy sequela. Methods The facial paralysis models were set up by facial-facial anastomosis in rat. The remodeling process of somatotopic organization and reinnervation of facial motor neurons were observed by Nissl staining and retrograde labeling methods 60 days after the operation. The ultrastructure of the facial motor neurons and its synaptic contacts were observed under transmission electron microscope （TEM） on the 90th day after the operation. Results 1. There were similar numbers and organization of facial motor neurons among the Nissl stained neurons on the both sides and FG （Fluoro Gold） labeled on the normal side. No necrosis or apoptotic appearances were found in facial motor neurons on the operational side by Nissl staining or uhrastructural observation. On the operational side the FG labeled motor neurons, representing reinnervating through the suture site successfully, decreased significantly compared with those of Nissl staining （P 〈 0.05）. There existed quite a few Nissl stained motor neurons withthout FG labelling and successful reinnervation on the operational side. 2. By double fluorescent retrograde tracing technique, some motor neurons innervating temporal branch were found distributed in subnucleus divisions that dominanted buccal branch. The ratio of such dislocated single-labeled motor neurons on the operational side were higher than that on the normal side （P 〈 0.05）. The double-labeled neurons by FG and FR （Fluoro Ruby） only appeared on the operational side. Conclusion After facial-facial anastomosis, the aberrant reinnervating can affect the genesis of post-palsy sequela. Further studies are needed on dormant motor neurons of such type for their role in the mechanism of facial nerve regeneration and post-paralysis sequleas such as synkinesis.