Neural repair in the CNS, which includes the brain and spinal cord, is notoriously difficult. Unlike Schwann cells in the PNS, oligodendrocytes that myelinate axons in the CNS do not support regeneration. Additionally, the CNS environment is inhibitory to axonal growth due to the presence of molecules like Nogo-A and chondroitin sulfate proteoglycans (CSPGs). The formation of a glial scar after injury further impedes regeneration by creating a physical and chemical barrier to axonal growth.
