Numbers of regenerated axons in tributary nerves following neonatal sciatic nerve crush in rat.

We determined numbers of regenerated axons in 5 tributary nerves 8 weeks after the complete axonal loss that follows crush of newborn rat sciatic nerve. The major findings are: (1) that proportionately many more axons are lost in cutaneous than in muscle nerves, (2) that myelinated axons are greatly increased over normal in two of the muscle nerves, and (3) that unmyelinated axons are normal or close to normal in muscle nerves. The major conclusions are: (1) there is a different pattern of regeneration in cutaneous as compared to muscle nerves after neonatal sciatic nerve crush, and (2) the responses after neonatal crushes are different than after adult nerve crushes.