Effects of motor and sensory nerve transplants on amount and specificity of sciatic nerve regeneration.
Nerve regeneration after complete transection does not allow for adequate functional recovery mainly because of lack of selectivity of target reinnervation. We assessed if transplanting a nerve segment from either motor or sensory origin may improve specifically the accuracy of sensory and motor reinnervation. For this purpose, the rat sciatic nerve was transected and repaired with a silicone guide containing a predegenerated segment of ventral root (VR) or dorsal root (DR), compared to a silicone guide filled with saline. Nerve regeneration and reinnervation was assessed during 3 months by electrophysiologic and functional tests, and by nerve morphology and immunohistochemistry against choline acetyltransferase (ChAT) for labeling motor axons. Functional tests showed that reinnervation was successful in all the rats. However, the two groups with a root allotransplant reached higher degrees of reinnervation in comparison with the control group. Group VR showed the highest reinnervation of muscle targets, whereas Group DR had higher levels of sensory reinnervation than VR and saline groups. The total number of regenerated myelinated fibers was similar in the three groups, but the number of ChAT+ fibers was slightly lower in the VR group in comparison with DR and saline groups. These results indicate that a predegenerated root nerve allotransplant enhances axonal regeneration, leading to faster and higher levels of functional recovery. Although there is not clear preferential reinnervation, regeneration of motor axons is promoted at early times by a motor graft, whereas reinnervation of sensory pathways is increased by a sensory graft.
Lago
Natalia
N
Group of Neuroplasticity and Regeneration, Department of Cell Biology, Physiology and Immunology, and Institute of Neuroscience, Universitat Autònoma de Barcelona, Bellaterra, Spain.
Rodríguez
Francisco J
FJ
Guzmán
Mónica S
MS
Jaramillo
Jéssica
J
Navarro
Xavier
X
D000200:Action Potentials / Q000502:physiology / Q000528:radiation effects; D000818:Animals; D018959:CD57 Antigens / Q000378:metabolism; D002795:Choline O-Acetyltransferase / Q000378:metabolism; D004558:Electric Stimulation / Q000379:methods; D004576:Electromyography; D005260:Female; D009416:Nerve Regeneration / Q000502:physiology*; D009431:Neural Conduction / Q000502:physiology / Q000528:radiation effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D020127:Recovery of Function / Q000502:physiology*; D020426:Sciatic Neuropathy / Q000601:surgery*; D012825:Silicon; D013126:Spinal Nerve Roots / Q000502:physiology*; D013997:Time Factors; D016378:Tissue Transplantation
D018959:CD57 Antigens; D002795:Choline O-Acetyltransferase; D012825:Silicon