Kruspe M, Thieme H, Guntinas-Lichius O, Irintchev A
Department of Otorhinolaryngology, Jena University Hospital, Lessingstrasse 2, D-07743 Jena, Germany.
Department of Otorhinolaryngology, Jena University Hospital, Lessingstrasse 2, D-07743 Jena, Germany.
Neuroscience. 2014 Nov 7;280:73-87. doi: 10.1016/j.neuroscience.2014.08.051. Epub 2014 Sep 9.
The rat femoral nerve is a valuable model allowing studies on specificity of motor axon regeneration. Despite common use of this model, the functional consequences of femoral nerve lesions and their relationship to precision of axonal regeneration have not been evaluated. Here we assessed gait recovery after femoral nerve injuries of varying severity in adult female Wistar rats using a video-based approach, single-frame motion analysis (SFMA). After nerve crush, recovery was complete at 4 weeks after injury (99% of maximum 100% as estimated by a recovery index). Functional restoration after nerve section/suture was much slower and incomplete (84%) even 20 weeks post-surgery. A 5-mm gap between the distal and proximal nerve stumps additionally delayed recovery and worsened the outcome (68% recovery). As assessed by retrograde labeling in the same rats at 20 weeks after injury, the anatomical outcome was also dependent on lesion severity. After nerve crush, 97% of the femoral motoneurons (MNs) had axons correctly projecting only into the distal quadriceps branch of the femoral nerve. The percentage of correctly projecting MNs was only 55% and 15% after nerve suture and gap repair, respectively. As indicated by regression analyses, better functional recovery was associated with higher numbers of correctly projecting MNs and, unexpectedly, lower numbers of MNs projecting to both muscle and skin. The data show that type of nerve injury and repair profoundly influence selectivity of motor reinnervation and, in parallel, functional outcome. The results also suggest that MNs' projection patterns may influence their contribution to muscle performance. In addition to the experiments described above, we performed repeated measurements and statistical analyses to validate the SFMA. The results revealed high accuracy and reproducibility of the SFMA measurements.
大鼠股神经是一种用于研究运动轴突再生特异性的重要模型。尽管该模型被广泛使用，但股神经损伤的功能后果及其与轴突再生精度的关系尚未得到评估。在此，我们采用基于视频的单帧运动分析（SFMA）方法，评估成年雌性Wistar大鼠不同严重程度股神经损伤后的步态恢复情况。神经挤压伤后，损伤后4周恢复完全（恢复指数估计为最大值100%的99%）。神经切断/缝合后的功能恢复则慢得多且不完全（84%），即使在术后20周也是如此。神经断端之间5毫米的间隙进一步延迟了恢复并使结果恶化（恢复率68%）。通过对同一批大鼠损伤后20周进行逆行标记评估，解剖学结果也取决于损伤的严重程度。神经挤压伤后，97%的股运动神经元（MNs）轴突正确地仅投射到股神经的远端股四头肌分支。神经缝合和间隙修复后，正确投射的MNs百分比分别仅为55%和15%。回归分析表明，更好的功能恢复与更多正确投射的MNs相关，出乎意料的是，与投射到肌肉和皮肤的MNs数量减少也相关。数据表明，神经损伤和修复的类型深刻影响运动再支配的选择性，同时也影响功能结果。结果还表明，MNs的投射模式可能影响它们对肌肉性能的贡献。除了上述实验外，我们还进行了重复测量和统计分析以验证SFMA。结果显示SFMA测量具有高准确性和可重复性。
