GLUCOCORTICOID EFFECTS ON AXONAL REGENERATION OF RETINAL GANGLION-CELLS IN-VITRO

Although glucocorticoids are commonly used for the treatment of optic nerve inflammations, little is known about direct effects of steroids on retinal nerve cells. In this study, the neuritogenic effect of pred nisolone on retinal ganglion cells was investigated using retinal orga n cultures derived from adult rats and embryonic chickens. The numbers of axons growing from retinal ganglion cells (RGC) in vitro were coun ted to measure the regenerative propensity at various corticosteroid c oncentrations. Prednisolone exerted a dose-dependent neuritogenic infl uence on RGC of either origin. The effect was highest at a concentrati on of 25 mu g/ml culture medium, where axon numbers increased to 237% (rat) and 166% (chick) of the control values. This was highly signific ant (t-test: P < 0.01 and P < 0.005, respectively). High corticosteroi d concentrations (>125 mu g/ml) produced toxic effects, as revealed by low axon numbers as well as morphological alterations of the explants .