Uschold Timothy, Robinson Grant A, Madison Roger D
Duke University, NC 27710, USA.
Exp Neurol. 2007 May;205(1):250-6. doi: 10.1016/j.expneurol.2007.02.005. Epub 2007 Feb 21.
The key to recovery of function following peripheral nerve lesions is guiding axons back to their original target end-organs. The parent femoral nerve splits into two comparable terminal pathways: one to the muscle and the other to the skin. Normally, motor neurons only innervate the pathway to the muscle, but after the parent nerve is repaired regenerating motor neurons are often misrouted to the skin. When the muscle and skin pathways remain connected to their respective targets after the parent nerve is repaired, reinnervation favors the muscle pathway. If contact with the muscle is instead prevented, reinnervation favors the pathway to the skin. Here we examine whether shortening the skin pathway can alter motor reinnervation accuracy when the muscle pathway remains connected to the muscle. We demonstrate that reducing the influence of the skin pathway results in a more rapid and extensive reinnervation of the muscle pathway. These findings suggest that the relative balance of trophic influences from the pathways and their end-organs is an important determinant of motor neuron regeneration accuracy, and that the muscle pathway by itself is not the primary regulator for regeneration accuracy of motor neurons.
周围神经损伤后功能恢复的关键在于引导轴突回到其原始靶终末器官。股神经主干分为两条类似的终末通路：一条通向肌肉，另一条通向皮肤。正常情况下，运动神经元仅支配通向肌肉的通路，但在修复主干神经后，再生的运动神经元常误导向皮肤。当主干神经修复后肌肉和皮肤通路仍与各自靶标相连时，再支配有利于肌肉通路。相反，如果阻止与肌肉的接触，再支配则有利于通向皮肤的通路。在此，我们研究当肌肉通路仍与肌肉相连时，缩短皮肤通路是否能改变运动再支配的准确性。我们证明，减少皮肤通路的影响会导致肌肉通路更快、更广泛地再支配。这些发现表明，来自通路及其终末器官的营养影响的相对平衡是运动神经元再生准确性的重要决定因素，并且肌肉通路本身并非运动神经元再生准确性的主要调节因子。
