Immunohistochemical evidence for sprouting of ventral root afferents after neonatal sciatic neurectomy in the rat

The present study demonstrates that afferent fibers in the rat ventral root sprout after transection of the neonatal sciatic nerve. The key data are that the number of unmyelinated fibers increased dramatically in the L5 ventral roots and about half of these unmyelinated fibers were labeled with antibody to growth associated phosphoprotein (GAP-43), suggesting that they are regenerating axons. Furthermore, these fibers survived in the distal stump of the acutely cut ventral root, suggesting that they are afferent fibers. The results provide direct evidence for sprouting of afferent fibers in the ventral root induced by a neonatal peripheral nerve lesion.