Morphological and electrophysiological evidence for regeneration of transected spinal cord fibers and restoration of motor functions in adult rats

After 2/3 transection of the right ninth thoracic spinal cord of an adult rat, a chitosan tube seeded with L-poly-lysine was implanted between the rostral and caudal end of the lesioned cord. Twelve months after the operation, regeneration of myeli-nated and non-myelinated axons and new blood vessels were observed along the wall of the chitosan tube implanted under an electron microscope. Somatosensory evoked potentials (SEP) could be consistently recorded from the left somatosensory cortex following electrical stimulation of the right hind limb, while transcranial magnetic stimulation of the left motor cortex could also evoke motor activity from the right hind limb. The present result suggests that implanted chitosan tube might be useful in regenera-tion of injured nerve fibers of the spinal cord resulting in a long-term restoration of motor functions.