NG2 and phosphacan are present in the astroglial scar after human traumatic spinal cord injury

One major class of growth-inhibitory molecules associated with CNS scar tissue is the family of chondroitin sulphate proteoglycans (CSPGs). These proteins are expressed throughout the developing and adult CNS and are associated with several growth-associated extracellular molecules. Following SCI in experimental animals, pharmacological interventions involving the degradation of lesion-induced CSPGs demonstrated a substantially enhanced regeneration of lesioned axons into and beyond the injury site and a significant functional recovery by treated animals. Experimental investigations into the role of individual members of the CSPG family revealed distinct expression patterns and functions in the traumatically injured CNS. We have performed a more detailed immunohistochemical investigation on the expression pattern of distinct members of the CSPG family, namely NG2, neurocan, versican and phosphacan in samples of post mortem human spinal cord, taken from patients who died at a range of survival times following severe traumatic SCI of the maceration type. The distribution pattern of individual members of the CSPG family varies significantly after human SCI. NG2 and phosphacan are both present in the evolving astroglial scar and might therefore play an important role in the blockade of successful CNS regeneration. Neurocan and versican are exclusively present in the lesion epicentre, associated with Schwann cells. They are present in the myelin sheaths of invading peripheral nerve fibres from lesioned dorsal roots and are not associated with regenerating CNS nerve fibres. As these results are not only in accordance with experimental studies but also reveal significant differences, they again point to the importance of correlative investigations in human post mortem tissue.