Regeneration of damaged axons

Following injury to the central nervous system the regenerating nerves need to regrow through the site of damage, but scarring in this area leads to the expression of proteins that inhibit axon growth. Proteins modified by the addition of chondroitin sulphates — a class of sugars — are one group of molecules involved in this inhibition. In the May Nature Neuroscience Lawrence Moon and colleagues at the Physiological Laboratory, University of Cambridge, UK report that chemical removal of these sugar groups permits regrowth through the injured site (Nat Neurosci 2001, 4:465-466).

Moon et al cut axons in the adult rat nigrostriatal tract, the dopamine-releasing neurons that degenerate in patients with Parkinson's disease. The injury resulted in scarring of the neural tissue, accompanied by a local increase in the expression of proteins bearing chondroitin sulphate groups — identified by immunolabelling. In control animals, no nerve regrowth was seen across this scar. ...