Efficacy of various antioxidants in the protection of the retinal pigment epithelium from oxidative stress

Abstract

Dov B Kagan, Hong Liu, Cindy ML HutnikIvey Eye Institute, St Joseph's Hospital, London, ON, CanadaBackground: Oxidative stress induced retinal pigment epithelium (RPE) dysfunction is hypothesized to be fundamental in the pathogenesis of age-related macular degeneration (AMD). This study investigated whether vitamin C, vitamin C phosphate, vitamin E, propofol, betaxolol, and N-acetyl cysteine (NAC) protect human RPE cells from oxidative stress.Methods: ARPE-19 cells were pretreated with the compounds under investigation. The chemical oxidant tert-butyl hydroperoxide (t-BOOH) was used to induce oxidative stress. Cell viability was determined using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay.Results: Exposure to t-BOOH resulted in a dose- and time-dependent reduction in ARPE-19 cell viability. Compared with cells given t-BOOH alone, vitamin E and NAC pretreated cells had significantly improved viability, propofol and betaxolol pretreated cells had no significant difference in viability, and vitamin C and vitamin C phosphate pretreated cells had significantly reduced viability.Conclusion: Of the compounds studied, only vitamin E and NAC significantly mitigated the effects of oxidative stress on RPE cells. Because of their potential therapeutic value for AMD patients, these and other RPE protective compounds continue to merit further investigation.Keywords: age-related macular degeneration, N-acetyl cysteine, vitamin C, vitamin E, propofol, betaxolol