External Factors, Produced by Growing Nerves, Trigger a Regenerative Response in a Non-Regenerative Central Nervous System: Purification and Mode of Action

摘要

Mammalian central nervous system (CNS) neurons have negligible posttraumatic regenerative capacity while the nerves of lower vertebrates, as well as the peripheral nervous system (PNS) of mammals regenerate spontaneously after the injury. We found that application soluble substances derived from growing nerves, (in the form of conditioned media, of regenerating fish optic nerves and of newborn rabbit optic nerves to injured adult rabbit optic nerves. The regeneration-like response involved a general increase in protein synthesis in the retina; selective increase in synthesis of a few polypeptides in the retina; and sprouting from the retina in vitro. We succeeded to demonstrate during the first year of this support that the active conditioned media causes environmental modifications manifested by: (a) the appearance of new fibers adjacent to astrocytic processes in area which otherwise seemed to be a scar tissue area (b) change in the profile of the nerve-derived proteins, e.g. an increase in a 12 KDa polypeptide which might be a second mediator in the cascade of events leading to regeneration, (c) increase in thymidine incorporation (d) increase in laminin distribution- a key extracellular matrix protein required for growth. Keywords: Neurogenesis. (KT)