Fig. 1. Schematic diagram illustrating the process of degeneration and regeneration after PNI.

When normal nerves (a) suffer from physical injury, the portion of the lesion site and its distal stump undergo destruction and breakdown and produce myelin debris. This degenerative process is called WD (b). Then, SCs recruit macrophages to scavenge degenerated myelin fragments (c). Meanwhile, SCs proliferate and migrate alone the basal lamina to form bands of Büngner, which guides axon to reinnervate towards the corresponding target (d).