REGENERATION OF PERIPHERAL NERVE IN HETEROGENIC NERVE GRAFT / 解剖学报

ABSTRACT

Nerve segments were excised from the posterior limb of the adult dog and treated by repeated freezing and thawing for five times. A segment about 5 mm long was removed from the right tibial nerve proximal to the popliteal fossa of each experimental adult rabbit, and 8 mm of nerve segment from the dog prepared as above was transplanted in the gap. Both the proximal and distal ends of the tibial nerve of host rabbits were sutured to the graft nerve of the donor dog. The grafts were excised together with the sutured cut ends of the recipient tibial nerve at 3, 4, 5, 6, 7, 15, 18, and 31 weeks after transplantation. The regenerating nerve fibers were found by light microscope from the proximal end of the right tibial nerve to the graft, and from the graft to the distal part of the tibial nerve at 3, 4, 5, 6, 7, 15, 18 and 31 weeks. Under electron microscope regenerating myelinated and unmyelinated fibers were found to be separate or in fascicle in the graft and the distal segment of the tibial nerve at the above survival time after transplantation. Perineurium was seen surrounding the regenerating nerve fascicles. Neurotubules, neurofilaments and mitochondria were found in the regenerating axons. The diameter of the regenerating myelinated fibers with long survival time after transplatation was thicker than that with short survival time. Repeated freezing and thawing reduced the antigenicity of the heterogenic nerve that it was not rejected after transplantation, and induced the regenerating nerve fibers of the host grow into the graft nerve and extend distally.