The invention is generally directed to treatment of neuronal injury. In particular, the invention is directed to reducing axonal retraction (&ldquo；dieback&rdquo；) that occurs as a result of the interaction of activated macrophages with dystrophic axons that are produced during nervous system acute or chronic injury. The invention is also directed to promoting axonal growth/regeneration. The invention is specifically directed to using stem cells or their secreted cellular factors, such as would be produced in conditioned cell culture medium, to ameliorate or prevent axonal dieback and/or promote growth/regeneration of axons.
