P 403 Title: Trans-scleral vs transpupillary diode photo-coagulation: Experimental histopathologic study

PURPOSE: We studied the effects of exposure to mitomycin C and 5-Fluorcuracil to human RPE cultures, in growth inhibition and citoxicity. METHODS: 1) Growth inhibition: RPE cultures (3.000 cells/well) were exposed to different concentrations of mitomycin C and 5-Fluorouracil, and cell viability (MTT test) was evaluated 48h, 72h and 96h after. 2) Citotoxicity: RPE cultures (10.000 cells/well) were exposed to different concentrations of mitomVcin C and 5-Fluorouracil, and cell viability (MT? test) was evaluated 96h after. RESULTS: 1) Growth inhibition: IC,o (!Jcl/ml) o= dose that produced 50% RPE growth inhibition was at 48 h 0.86; and at 96 h 0.43 for the mitomycin, whereas it ias at 48 h 6.311; and at 96h 1.36 for 5-fluorouracil. 2) Citotoxicity: IC,, (pg/ml) or dose that produced 50% RPE zitotoxicity was at 96 h 0.09 for the mitomvcin. whereas it was at 96h 0.55 for 5-fluorouracil. CONCLUSIONS: Mitomycin C at lower doses has a higher effect on RPE growth inhibition and citotoxicity than 5-fluorouracil.