The role of GAP-43 and growth factors on axon elongation of rat retinal ganglion cells through peripheral nervous system tissue grafts.

摘要

The goals of this dissertation were to determine if GAP-43 was upregulated in rat retinal ganglion cells (RGC's) after optic nerve transection, if peripheral nerve grafting augmented the upregulation of GAP-43, if transected RGC axons would grow into acellular nerve grafts in which specific growth factors were released, and if growth factor replacement in these grafts would rescue RGCs.;Quantitative 2D gel autoradiography was used to assess changes in the synthesis and transport of GAP-43. Two weeks after optic nerve transection, GAP-43 was transiently upregulated compared to normal adult controls. Following transection and nerve-grafting, however, GAP-43 shows a sustained upregulation for up to 6 weeks. Retrograde labeling of RGCs following application of horseradish peroxidase to the grafts, and GAP-43 immunocytochemistry of retinas in nerve-grafted animals, were used to determine if RGC's which show an augmented GAP-43 immunoreactivity are also extending axons into the grafts. While all RGCs growing axons into the grafts were positive for GAP-43, many GAP-43 positive cells were not associated with axon growth into the grafts. We conclude that the presence of a nerve graft sustains the upregulation of GAP-43, and that this upregulation is correlated with an increased potential for nerve growth.;Basic fibroblast growth factor (bFGF) or insulin-like growth factor-I (IGF-I) were slow-released from Elvax