Induced expression of polysialic acid in the spinal cord promotes regeneration of sensory axons.

After spinal cord injury axonal regeneration is prevented by glial scar formation. In this study we examined whether induced expression of polysialic acid (PSA) in the lesion site would render the glial scar permissive to axonal regeneration after dorsal column transection. PSA was induced by lentiviral vector-mediated expression of polysialyltransferase (LV/PST). PSA expression increased astrocyte infiltration and permitted the penetration of regenerating axons across the caudal border of the lesion and into the lesion cavity. In LV/PST-injected animals with a peripheral nerve-conditioning lesion, 20 times more axons grew into the lesion cavity than those LV/GFP-injected plus conditioning lesion, and some axons grew across the cavity and extended to the rostral cord, while in LV/GFP group most ascending axons terminated at the caudal border of the lesion. Our result suggests that induced expression of PSA can provide a favorable environment for axonal regeneration.