Stimulation of axonal sprouting by trophic factors immobilized within the wound core.

Traumatic injury to the CNS results in peri-wound sprouting without significant axonal growth beyond the lesion edge. We have previously demonstrated that dopaminergic sprouting in the injured striatum follows an increasing gradient of BDNF and GDNF expression, with sprouting ceasing at the point of maximal factor expression. Progressively more complicated associations of sprouting fibers with increasingly activated microglia and macrophages suggest these factors are localized to the cell surface.