DEXAMETHASONE-INDUCED PROLIFERATION OF CULTURED RETINAL-PIGMENT EPITHELIAL-CELLS

Dexamethasone (DEX) is a glucocorticoid that is widely used after vitr eoretinal surgery and may have mitogenic properties. This study was in itiated to determine if human cultured retinal pigment epithelium (RPE ) cells express glucocorticoid receptor and proliferate in response to DEX stimulation. Glucocorticoid receptor mRNA was detected in RPE cel ls by means of reverse transcriptase polymerase chain reaction. To det ermine the effect of DEX on RPE cell proliferation in vitro, we cultur ed human RPE cells with various concentrations of DEX for 5 days and d etermined the effects on cell number and incorporation of tritiated th ymidine. DEX treatment with a DEX dose of 1 mu g/ml in the presence or absence of serum resulted in a maximal 2-3 times increase in cell num ber. Autoradiography after thymidine incorporation revealed a greater than 2-fold increase in incorporating cells at this same dose. These r esults indicate that DEX causes cultured human RPE cells to proliferat e and suggest that it may have a growth factor-like action.