Bain J R, Veltri K L, Chamberlain D, Fahnestock M
Division of Plastic Surgery, Department of Surgery, McMaster University, 1200 Main Street West, Hamilton, Ontario, L8N 3Z5, Canada.
Neuroscience. 2001;103(2):503-10. doi: 10.1016/s0306-4522(00)00577-7.
Prolonged muscle denervation results in poor functional recovery after nerve repair. The possible protective effect of temporary sensory innervation of denervated muscle, prior to motor nerve repair, has been examined in the rat. Soleus and gastrocnemius muscles were denervated by cutting the tibial nerve, and the peroneal nerve was then sutured to the transected distal tibial nerve stump either immediately or after two, four or six months. In half of the animals with delayed repair, the saphenous (sensory) nerve was temporarily attached to the distal nerve stump. Muscles were evaluated three months after the peroneal-to-tibial union, and were compared with each other, with unoperated control muscles and with untreated denervated muscles. After four to six months of sensory "protection", gastrocnemius muscles weighed significantly more than unprotected muscles, and both gastrocnemius and soleus muscles exhibited better preservation of their structure, with less fiber atrophy and connective tissue hyperplasia. The maximum compound action potentials were significantly larger in gastrocnemius and soleus muscles following sensory protection, irrespective of the delay in motor nerve union. Isometric force, although less than in control animals and in those with immediate nerve repair, remained reasonably constant after sensory protection, while in unprotected muscles there was a progressive and significant decline as the period of denervation lengthened. We interpret these results as showing that, although incapable of forming excitable neuromuscular junctions, sensory nerves can nevertheless exert powerful trophic effects on denervated muscle fibers. We propose that these findings indicate a useful strategy for improving the outcome of peripheral nerve surgery.
长期肌肉去神经支配会导致神经修复后功能恢复不佳。在大鼠身上研究了在运动神经修复之前对去神经支配的肌肉进行临时感觉神经支配可能产生的保护作用。通过切断胫神经使比目鱼肌和腓肠肌去神经支配，然后立即或在两、四或六个月后将腓总神经缝合到切断的胫神经远端残端。在一半延迟修复的动物中，将隐神经（感觉神经）临时连接到远端神经残端。在腓总神经与胫神经吻合三个月后对肌肉进行评估，并相互比较，同时与未手术的对照肌肉和未治疗的去神经支配肌肉进行比较。经过四到六个月的感觉“保护”后，腓肠肌的重量明显高于未受保护的肌肉，并且腓肠肌和比目鱼肌的结构都得到了更好的保留，纤维萎缩和结缔组织增生较少。无论运动神经吻合延迟情况如何，感觉神经保护后的腓肠肌和比目鱼肌的最大复合动作电位都明显更大。等长力虽然低于对照动物和立即进行神经修复的动物，但在感觉神经保护后保持相对稳定，而在未受保护的肌肉中，随着去神经支配时间的延长，等长力会逐渐且显著下降。我们将这些结果解释为表明，感觉神经虽然无法形成可兴奋的神经肌肉接头，但仍能对去神经支配的肌纤维发挥强大的营养作用。我们认为这些发现表明了一种改善周围神经手术效果的有用策略。
