Ability of adult rat ganglion cells to regrow axons in vitro can be influenced by fibroblast growth factor and gangliosides.

The ability of lesioned adult retina ganglion cells (RGC) to survive and regrow axons in vitro was investigated in retina organ cultures under chemically defined conditions. Factors which are known to either affect the RGC survival like the basic fibroblast growth factor (FGF) or influence neurite outgrowth like gangliosides were assayed by recording the course of prelabeled RGC degeneration in vitro and the number and length of regrowing RGC axons from explanted retinal pieces. Administration of basic FGF significantly slowed down the decrease in the number of RITC-prelabeled RGC in the cultured retinae. In addition, in the presence of gangliosides (GM1, GD1a, GD1b GT1b), the numbers of regrown RGC axons (Thy 1-immunostained) increased dramatically as compared to controls. The data indicate that adult neurons with an intrinsic ability to regenerate axons can respond to substances with neurotrophic or neurite-promoting activities in tissue cultures.