Survival and regeneration of motoneurons in adult rats by reimplantation of ventral root following spinal root avulsion.

The present study examines whether reimplantation of the ventral root could prevent motoneuron death after root avulsion. In the control animals about 65% or 39% of motoneurons survived at 3 or 6 weeks post-injury respectively. More than 60% of them expressed nitric oxide synthase (NOS). In contrast, in animals with ventral root reimplantation, nearly 90% or 80% of motoneurons survived at 3 or 6 weeks post-injury respectively. Expression of NOS due to root avulsion was significantly inhibited in these experimental animals. More interestingly, about 80% of the surviving motoneurons were found to regenerate their axons into the reimplanted ventral root, and all of these regenerating motoneurons were NOS negative. Results of the present study show that reimplantation of avulsed ventral root can greatly enhance motoneuron survival and the surviving motoneurons can regrow their axons into the original ventral root.