Vascularized peripheral nerve trunk autografted in the spinal cord: a new experimental model in adult rats.

Abstract

OBJECTIVE: To investigate the effect of vascularized peripheral nerve trunk autografted in spinal cord. METHODS: With modern microsurgical technique, vascularized peripheral median and ulnar nerve trunk autografted in the upper thoracic region of the spinal cord were established in 20 female adult rats. The origin and the termination of axons in the graft were studied by retrograde neuronal labeling with horseradish peroxidase (HRP). Cord, nerve grafts and some normal median an d ul nar nerves in the right upper limb were removed and sectioned for Bielschowsky's silver stain and haematoxylin and eosin (H&E) stain. Light and electron microscopic examination and electrophysiological examination were applied. RESULTS: The grafts were innervated by many new fibers. Studies with HRP indicated that new axons in graft were originated from intrinsic cent ral nervous system (CNS) neurons with their cell bodies from brain stem to s acral segments of spinal cord. Other axons arose from dorsal root ganglia at the level of graft and at least 19 distal segments to them. Together with electron microscopy, electrophysiological examination, silver and H&E stain, the results demonstrated that vascularized peripheral nerve trunk grafted in spinal cord attracted many neurons to grow into the nerve grafts. CONCLUSIONS: The findings implicate that CNS is able to regenerate much better in vascularized nerve autografted in spinal cord.