Success of regeneration of peripheral nerve axons in rats after injury at different postnatal ages.

Electrophysiological experiment have been carried out on rats to see if the age at which a peripheral nerve injury occurs influences the success of regeneration. The assessment was made on the basis of two measures of peripheral nerve regeneration; the extent to which axons manage to grow across the injury site and into the distal stump, and their ability to resupply cutaneous structures with functional endings. Regeneration after nerve transection of both myelinated and unmyelinated axons was studied. The results showed that, apart from rats injured when 2 weeks old, the age at which injury occurred, over the range 4-40 weeks, had little bearing on the overall success of skin reinnervation. The 2-week-old rats showed significantly poorer recovery.