Functional projection of regenerated rat sural nerve axons to the hindpaw skin after sciatic nerve lesions.
The functional regeneration of polymodal C-fibers and low-threshold mechanoreceptive axons in the rat sural nerve was evaluated 3 months after a sciatic nerve crush lesion or neurotomy and suture. The distribution of polymodal C-fibers was tested through stimulation-induced extravasation of Evans blue albumin in the foot skin. As judged from the area of stained skin, the polymodal sural C-fibers regenerated efficiently after both lesion types. In regenerates, though, the borders of the stained domain were less clearly defined than in controls, and there were minor territorial abnormalities. The Evans blue-stained area on the unoperated side in neurotomy/suture cases was significantly smaller than in normal control animals. The area covered by low-threshold mechanoreceptors in the foot skin was tested through gentle mechanical stimulation with a blunt probe and electrophysiological recording from the sural nerve. In regenerates the foot skin area covered by functional low-threshold mechanoreceptors turned out to be reduced on the operated side compared to controls, particularly after neurotomy/suture. We conclude that sural nerve regeneration is accompanied by a spatially more complete reestablishment of functional C-fiber-related cutaneous polymodal nociceptors than of functional cutaneous low-threshold mechanoreceptors.
Povlsen
B
B
Department of Hand and Plastic Surgery, University of Linköping, Sweden.
Hildebrand
C
C
Wiesenfeld-Hallin
Z
Z
Stankovic
N
N
D000818:Animals; D001369:Axons / Q000502:physiology*; D003714:Denervation; D005070:Evans Blue; D005260:Female; D005528:Foot; D008465:Mechanoreceptors / Q000502:physiology; D009409:Nerve Crush; D009412:Nerve Fibers / Q000502:physiology; D009416:Nerve Regeneration; D009434:Neural Pathways / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D012584:Sciatic Nerve / Q000293:injuries / Q000502:physiology*; D012867:Skin / Q000294:innervation*; D013497:Sural Nerve / Q000502:physiology*; D013537:Sutures
D005070:Evans Blue