THE DISTRIBUTION OF C-FOS PROTEIN IMMUNOLABELED CELLS IN THE SPINAL-CORD OF THE RAT AFTER ELECTRICAL AND NOXIOUS THERMAL-STIMULATION FOLLOWING SCIATIC-NERVE CRUSH, OR TRANSECTION AND REPAIR
J. Hongpaisan et C. Molander, THE DISTRIBUTION OF C-FOS PROTEIN IMMUNOLABELED CELLS IN THE SPINAL-CORD OF THE RAT AFTER ELECTRICAL AND NOXIOUS THERMAL-STIMULATION FOLLOWING SCIATIC-NERVE CRUSH, OR TRANSECTION AND REPAIR, Restorative neurology and neuroscience, 5(4), 1993, pp. 249-261
The distribution of stimulus evoked Fos protein-like immunoreactivity
in spinal cord neurons was studied in adult rats at different survival
times after sciatic nerve crush or transection and epineural repair.
Fos protein-like immunoreactivity was induced either by electrical sti
mulation of the sciatic nerve central to the injury, at C-fiber streng
th, at 21, 39, and 92 days post-lesion, or by noxious heat applied to
the skin of the hind paw 92 days post-lesion. The contralateral uninju
red side served as control. The results with electrical stimulation sh
owed, with some exceptions, that the distribution of c-fos expressing
cells in the spinal cord on the normal and on the previously injured s
ide were similar after both crush and transection with repair. The mai
n finding was an up-regulation of the number of Fos protein immunoreac
tive neurons in the inner portion of Rexed's lamina II. The results fo
llowing heat stimulation 92 days post-lesion showed a decrease in the
number of labeled neurons in most laminae after both types of injury.
This was more pronounced in cases with sciatic nerve transection with
repair compared to cases with crush. The results indicate time-depende
nt alterations in the distribution of stimulus evoked c-fos expression
in spinal cord neurons during regeneration after nerve injury. Furthe
rmore, the results from heat stimulation may indicate a slower and per
haps more incomplete restoration process after transection with repair
than after crush.