The role of proteoglycans in Schwann cell/astrocyte interactions and in regeneration failure at PNS/CNS interfaces.

In the dorsal root entry zone (DREZ) peripheral sensory axons fail to regenerate past the peripheral nervous system/central nervous system (PNS/CNS) interface. Additionally, in the spinal cord, central fibers that regenerate into Schwann cell (SC) bridges can enter but do not exit at the distal Schwann cell/astrocyte (AC) boundary. At both interfaces where limited mixing of the two cell types occurs, one can observe an up-regulation of inhibitory chondroitin sulfate proteoglycans (CSPGs).