Untrastructural study of repairing process on peripheral nerve

To finding out the repairing process of injured peripheral nerve,we observed the changes of ultrastructure of crymo\|injured sciatic nerve from beginning to 4th week in rats.The results showed that some newborn axon encysted with Schwann's cell was found besides degenerated nerve fibers in 3 days of crymo\|injury.A week later,newborn nerve fibers were riched in which unmyelinated fibers were much more than the myelinated fibers,Schwann's cell and microphagocyte phagocytosed the degenerated nerve fibers.After that,normal Schwann's cell and nerve fibers increased gradually and the degenerated substances decreased.Up to 4th week,there still were little phagocytosed medullary structure.Out observation revealed that sciatic nerve damaged by refrigeration began regeneration after 3days.A week later,medullary nerve fibers appeared and the repaired process basically finished until 4th week. 