Abstract
Fourteen Splague-Dawley rats were used to establish trigemianal painful mononeuropathy, and another ten to study histopathological changes in this model. A chronic compression injury to the trigeminal ganglion (TGCC) was induced. 5μl of medical silicone was injected through a plastic catheter that was placed beside the trigeminal ganglion via the foramen ovale. A head withdrawal latency from noxious heat was observed after the operation. A morphologic study was also performed on the infraorbital nerve, the trigeminal ganglion, and the trigeminal subnucleus caudalis. Rats after receiving the TGCC had a clear sign of heat-hyperalgesia from POD 3 to POD 30. Degenerating myelinated fibers such as myelin sphers were observed not only in the ipsilateral peripheral Aβ fibers but also in the trigeminal tract on POD 6, 15 and 24. Neuronal de/re-generation was observed with appearance of heat-hyperalgesia. Regenerating myelinated fibers were still observed after the sign of heat-hyperalgesia diminished. The results of this study indicated that heat-hyperalgesia is observed in the process of degeneration and regeneration.
