Sensory neurons regenerate more dominantly than motoneurons during the initial stage of the regenerating process after peripheral axotomy.

This study was designed to determine whether sensory neurons or motoneurons were dominant during the earlier stage of the regeneration process after peripheral axotomy. After transection of the right sciatic nerves of rats, epineurial end neurorrhaphy was performed. At 5, 7 and 14 days postoperatively, the nerves were re-transected at the positive pinch site, and their proximal stumps were exposed to the retrograde neurotracer, Fluoro-Gold (F-G). Seventy-two hours later, the lumbar spinal cords and the L4 and L5 dorsal root ganglia (DRG) were harvested and evaluated. The incidence and the intensity of F-G labelling in DRG were significantly higher than in anterior horns (AH). These results demonstrated that sensory neurons were more dominant than motoneurons in nerve regeneration.