Peripheral and spinal motor reorganization after nerve injury and repair.
Functional recovery after peripheral nerve injury depends on the amount as well as on the accuracy of reinnervation by regenerative axons. In this study, the rat sciatic nerve was subjected to crush injury or complete transection repaired by either (1) straight nerve suture, (2) crossed nerve suture of tibial and peroneal fascicles, or (3) silicone tubulization leaving a gap of 4 mm. The compound muscle action potentials (CMAP) of gastrocnemius, tibialis anterior and plantar muscles were recorded 90 days post operation to assess functional reinnervation and Fast Blue, Fluoro Gold and DiI were applied to the nerve branches projecting into these muscles to quantify morphological reinnervation. The CMAP amplitude achieved in gastrocnemius, tibialis anterior and plantar muscles was higher after nerve crush (86%, 82%, 65% of control) than after any surgical nerve repair (straight suture: 49%, 53%, 32%; crossed suture: 56%, 50%, 31%; silicone tube: 42%, 44%, 25%). The total number of labeled motoneurons, however, did not significantly differ between groups (control: 1238 +/- 82, crush: 1048 +/- 49, straight suture: 1175 +/- 106, crossed suture: 1085 +/- 84, silicone tube: 1250 +/- 182). The volume occupied by labeled motoneurons within the spinal cord was larger after surgical nerve repair than in crush or normal control animals, and fewer neurons showed abnormal multiple projections after crush (2.5%) or straight suture (2.2%) than following crossed suture (5%) or silicone tube (6%). In conclusion, nerve repair with a silicone tube leaving a short gap does not increase accuracy of reinnervation.
Department of Cell Biology, Physiology and Immunology, Universitat Autònoma de Barcelona, Spain.
Antoni
A
Valero-Cabré
Konstantin
K
Tsironis
Emmanouil
E
Skouras
Xavier
X
Navarro
Wolfram F
WF
Neiss
D000200:Action Potentials / Q000502:physiology; D000714:Anastomosis, Surgical; D000818:Animals; D019771:Axotomy; D004576:Electromyography; D005260:Female; D020007:Implants, Experimental; D009046:Motor Neurons / Q000473:pathology*; D018482:Muscle, Skeletal / Q000294:innervation* / Q000502:physiology*; D009409:Nerve Crush; D009416:Nerve Regeneration; D051381:Rats; D017208:Rats, Wistar; D020127:Recovery of Function; D012584:Sciatic Nerve / Q000293:injuries / Q000601:surgery*; D012825:Silicon; D013116:Spinal Cord / Q000473:pathology*; D013536:Suture Techniques
D012825:Silicon