Retinal ganglion cell survival and neurite regeneration in vitro after cell death period are dependent upon target derived trophic factor and retinal glial factor(s)

Retinal ganglion cells (RGCs) obtained from the rat retina after the cell death period were maintained in vitro by target derived retinal ganglion cell neurotrophic factor (RGNF). However, only 15% of surviving RGCs expressed neurites. On the other hand, when the culture was supplemented with retinal glia conditioned medium, nearly 80% of surviving RGCs expressed neurites which were longer than two cell diameter. Expression of neurites is not due to the presence of laminin in the glial conditioned medium as laminin coated substratum had no significant effect on the neurite growth from mature RGCs in the absence of glial factors.