Grosheva Maria, Guntinas-Lichius Orlando, Angelova Srebrina K, Kuerten Stefanie, Alvanou Athanasia, Streppel Michael, Skouras Emmanouil, Sinis Nektarios, Pavlov Stoyan, Angelov Doychin N
Department of Oto-Rhino-Laryngology, University of Cologne, Germany.
Exp Neurol. 2008 Jan;209(1):131-44. doi: 10.1016/j.expneurol.2007.09.016. Epub 2007 Sep 26.
Within a recent study on the recovery of vibrissae motor performance after facial nerve repair in blind (strain SD/RCS) and sighted (strain SD) rats, we found that, despite persisting myotopic disorganization in the facial nucleus, the blind animals fully restored vibrissal whisking. Searching for the morphological substrates of this improved recovery, we compared the amount of cytoskeletal proteins in the leading edge of elongating axons between both strains. Since our results showed an enhanced expression of neuronal class III beta-tubulin in the blind rats, we wondered whether this was due to an increased synthesis or to a delayed turnover of microtubules. In the present report, we approached this question applying established pharmacological agents to the transected buccal branch of the facial nerve in sighted Wistar rats perturbing either microtubule assembly towards stabilization (enhanced polymerization with 10 microg/ml taxol) or towards increased synthesis (challenged by destabilization with 100 microg/ml nocodazole and 20 microg/ml vinblastine). Evaluation of the effect(s) 2 months later included estimation of (i) vibrissae motor performance by video-based motion analysis, (ii) the degree of collateral axonal branching by double retrograde neuronal labeling with crystals of Fluoro-Gold and DiI and (iii) the pattern of motor end-plate reinnervation (proportions of mono- and poly-reinnervated) in the largest extrinsic vibrissal muscle, the m. levator labii superioris. We found that only stabilization of microtubules with 10 microg/ml taxol reduced intramuscular axonal sprouting and polyinnervation of the motor end-plates, which was accompanied by improved restoration of function.
在最近一项关于盲鼠（SD/RCS品系）和有视力的大鼠（SD品系）面神经修复后触须运动功能恢复的研究中，我们发现，尽管面神经核中肌位组织持续紊乱，但盲鼠的触须摆动功能完全恢复。为了寻找这种改善恢复的形态学基础，我们比较了两个品系中伸长轴突前缘细胞骨架蛋白的含量。由于我们的结果显示盲鼠中神经元III类β-微管蛋白的表达增强，我们想知道这是由于微管合成增加还是周转延迟所致。在本报告中，我们通过向有视力的Wistar大鼠的面神经颊支横断处应用既定的药物来解决这个问题，这些药物要么使微管组装向稳定方向发展（用10微克/毫升紫杉醇增强聚合），要么向增加合成方向发展（用100微克/毫升诺考达唑和20微克/毫升长春碱破坏稳定来挑战）。2个月后对效果的评估包括：（i）通过基于视频的运动分析估计触须运动性能；（ii）用荧光金和DiI晶体进行双逆行神经元标记来估计侧支轴突分支程度；（iii）在最大的外在触须肌即提上唇肌中评估运动终板再支配模式（单支配和多支配的比例）。我们发现，只有用10微克/毫升紫杉醇使微管稳定才能减少肌内轴突发芽和运动终板的多神经支配，同时功能恢复得到改善。
