Spector J G, Lee P, Derby A, Frierdich G E, Neises G, Roufa D G
Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, St. Louis, MO 63110.
Laryngoscope. 1993 May;103(5):548-58. doi: 10.1288/00005537-199305000-00013.
Previous reports suggest that exogenous nerve growth factor (NGF) enhanced nerve regeneration in rabbit facial nerves. Rabbit facial nerve regeneration in 10-mm Silastic tubes prefilled with NGF was compared to cytochrome C (Cyt. C), bridging an 8-mm nerve gap. Three weeks following implantation, NGF-treated regenerates exhibited a more mature fascicular organization and more extensive neovascularization than cytochrome-C-treated controls. Morphometric analysis at the midtube of 3- and 5-week regenerates revealed no significant difference in the mean number of myelinated or unmyelinated axons between NGF- and cytochrome-C-treated implants. However, when the number of myelinated fibers in 5-week regenerates were compared to their respective preoperative controls, NGF-treated regenerates had recovered a significantly greater percentage of myelinated axons than cytochrome-C--treated implants (46% vs. 18%, respectively). In addition, NGF-containing chambers reinnervated a higher percentage of myelinated axons in the distal transected neural stumps (49% vs. 34%). Behavioral and electrophysiologic studies demonstrated spontaneous and induced activities in the target muscles when approximately one third of the myelinated axons were recovered in the midchamber (1280 axons). Horseradish peroxidase (HRP) studies demonstrated retrograde axonal transport to the midchamber and proximal transected neural stump. PC12 bioassay demonstrated persistent NGF activity in the intrachamber fluids at 3 (5:1 dilution) and 5 (2:1 dilution) weeks of entubation. Electrophysiologic tests demonstrated a slow conduction velocity of a propagated electrical impulse (43.5 m/s-1 vs. 67 m/s-1) and shallow wide compound action potential. In wider defects (15-mm chambers) and longer entubation periods (7 weeks), no regeneration or NGF activity was seen. Therefore, exogenous NGF provides an early but limited neurotrophic effect on the regeneration of the rabbit buccal division of the facial nerve and a limited behavioral and physiological improvement in the target muscles.
先前的报告表明，外源性神经生长因子（NGF）可促进兔面神经的神经再生。将预先填充有NGF的10毫米硅橡胶管中的兔面神经再生情况与桥接8毫米神经间隙的细胞色素C（Cyt. C）进行比较。植入后三周，与细胞色素C处理的对照组相比，NGF处理的再生神经表现出更成熟的束状结构和更广泛的新生血管形成。对3周和5周再生神经的中管进行形态计量分析发现，NGF处理组和细胞色素C处理组植入物的有髓或无髓轴突平均数量没有显著差异。然而，当将5周再生神经中的有髓纤维数量与其各自的术前对照组进行比较时，NGF处理组再生神经中恢复的有髓轴突百分比显著高于细胞色素C处理组植入物（分别为46%和18%）。此外，含有NGF的腔室在远端横断神经残端中重新支配的有髓轴突百分比更高（49%对34%）。行为和电生理研究表明，当中腔中大约三分之一的有髓轴突恢复时（1280条轴突），靶肌肉会出现自发和诱导活动。辣根过氧化物酶（HRP）研究表明，轴突逆行运输至中腔和近端横断神经残端。PC12生物测定表明，插管3周（5:1稀释）和5周（2:1稀释）时，腔内液体中存在持续的NGF活性。电生理测试表明，传播的电冲动传导速度较慢（43.5米/秒对67米/秒），复合动作电位浅而宽。在更宽的缺损（15毫米腔室）和更长的插管期（7周）中，未观察到再生或NGF活性。因此，外源性NGF对兔面神经颊支的再生具有早期但有限的神经营养作用，并且对靶肌肉的行为和生理改善有限。
