INFLUENCE OF OXYGEN-FREE RADICALS AND FREE-RADICAL SCAVENGERS ON THE GROWTH-BEHAVIOR AND OXIDATIVE TISSUE-DAMAGE OF BOVINE RETINAL-PIGMENT EPITHELIUM-CELLS IN-VITRO

Purpose: This investigation was carried out to ascertain whether oxyge n free radicals can influence the growth behaviour and consecutive lip id peroxidation of retinal pigment epithelium (RPE) cells in vitro and whether scavengers can counteract these effects. Methods: The experim ental model was based on calf RPE cells. Hypoxanthine/xanthine oxidase (HX/XO) and superoxide dismutase/catalase (SOD/CAT) served as the rad ical generating system and scavengers, respectively. The components we re tested alone and in combination. Lipid peroxides were determined in culture supernatants by a thiobarbituric acid assay. Results: Concent rations of up to 100 mu mol/l of HX alone and 500/1000 mu U of XO alon e, as well as the application of the scavengers without the radical ge nerating system (HX/XO), had no effect. Dose-related reduction of cell growth and increase of lipid peroxidation were found with HX/XO treat ment (single dose of 500 and 1000 mu U/ml 24 h after seeding), After a pplication of 500 or 1000 mu U/ml of XO, CAT. when given alone (1200 U /ml), counteracted the effect of the radicals on cell growth and lipid peroxidation; SOD (300 U/ml) had no effect, A combination of SOD and CAT was no better than the effect of CAT alone. Conclusion: The preven tion of radical-induced reduction of cell growth and lipid peroxidatio n by scavengers supports trials of therapy using antioxidants and/or f ree radical scavengers for various ocular syndromes with RPE involveme nt.