Brown M C, Hardman V J
Brain. 1987 Jun;110 ( Pt 3):695-705. doi: 10.1093/brain/110.3.695.
The accuracy of reinnervation in peripheral nerves following second degree injuries, which do not disrupt the longitudinal continuity of the endoneurial sheaths, has been studied in rats. The sciatic nerve or lumbar spinal nerves (that is the extraspinal nerves before their fusion in the sciatic plexus) were crushed with fine watchmakers' forceps in neonatal and adult rats. In addition, the lumbar spinal nerves were frozen in a group of 5 adult rats. After allowing reinnervation to occur for 5 to 9 weeks, the motoneurons whose axons ran in the plantar nerve were labelled retrogradely with horseradish peroxidase. Their positions in the grey matter of the lumbar spinal cord were recorded and compared with those labelled from the contralateral unoperated plantar nerve. Very few errors of projection occurred after a crush lesion of the adult sciatic nerve but all the other lesions produced significant numbers of errors. The order, starting with the preparations with fewest errors was as follows (numbers in brackets = percentage of neurons misplaced): sciatic crush in adult (3%), sciatic crush in neonate (23%), spinal nerve freeze in adult (23%), spinal nerve crush in adult (35%), and spinal nerve crush in neonate (72%). It seems that a significant number of axonal growth cones cross endoneurial sheaths after crush or cryoinjuries. Explanations for the difference in observed reinnervation accuracy between young and old rats and between lesions in peripheral nerves and spinal nerves are discussed. The first is that axons in peripheral nerves in older rats have a less penetrable endoneurial membrane encasing them. The second is that the amount of misrouting is the same at all lesion sites but is much less easily detectable after sciatic lesions than spinal nerve lesions. This is because axons are organized in a 'musculotopic' manner in peripheral nerves and exchange of axon positions will occur largely between axons destined for the same peripheral target. In contrast, exchange of positions of axons in spinal nerves will lead to more overt errors because at this site axons destined for particular muscles do not lie side by side but are intermingled with axons innervating other peripheral targets.
在大鼠中研究了二度损伤后周围神经再支配的准确性，二度损伤不会破坏神经内膜鞘的纵向连续性。在新生大鼠和成年大鼠中，用精细的钟表匠镊子挤压坐骨神经或腰脊髓神经（即坐骨神经丛融合前的脊髓外神经）。此外，在一组5只成年大鼠中冷冻腰脊髓神经。在允许再支配发生5至9周后，用辣根过氧化物酶逆行标记其轴突在足底神经中走行的运动神经元。记录它们在腰脊髓灰质中的位置，并与对侧未手术的足底神经标记的位置进行比较。成年坐骨神经挤压损伤后很少发生投射错误，但所有其他损伤都产生了大量错误。错误最少的制剂顺序如下（括号内数字=神经元错位百分比）：成年坐骨神经挤压（3%）、新生坐骨神经挤压（23%）、成年脊髓神经冷冻（23%）、成年脊髓神经挤压（35%）和新生脊髓神经挤压（72%）。似乎在挤压或冷冻损伤后，大量轴突生长锥穿过神经内膜鞘。讨论了年轻和年老大鼠之间以及周围神经和脊髓神经损伤之间观察到的再支配准确性差异的原因。第一个原因是老年大鼠周围神经中的轴突被包裹在渗透性较低的神经内膜膜中。第二个原因是所有损伤部位的误路由量相同，但坐骨神经损伤后比脊髓神经损伤后更难检测到。这是因为周围神经中的轴突以“肌肉定位”方式组织，轴突位置的交换将主要发生在 destined for the same peripheral target 之间。相比之下，脊髓神经中轴突位置的交换将导致更明显的错误，因为在这个部位， destined for particular muscles 的轴突不是并排排列，而是与支配其他周围目标的轴突混合在一起。 （注：文档中“destined for the same peripheral target”和“destined for particular muscles”这两处表述似乎不完整，可能影响对译文的理解准确性，但按照要求进行了完整翻译。）
