Cerium Oxide Nanoparticles Protect Human Pigment Epithelium (RPE) Cells Against Hydrogen Peroxide (H2O2)-Induced Cell Death

Abstract

Purpose:: It has been reported that intravitreal injection of Cerium oxide nanoparticles protect photoreceptor cells against light-induced degeneration (Chen, J. , Patil, S. , Seal, S. and McGinnis, J. F. Nature Nanotech. 2006). In this study, the protective effects of Cerium nanoparticles against hydrogen peroxide (H₂O₂)-induced cell death of human retinal pigment epithelium (RPE) cells were examined.

Methods:: A human RPE cell line (ARPE-19) was used. The RPE cells were grown in DMEM with 10% FBS and 10IU/ml of penicillin in sterilized six well plates. Cells were grown to confluence in an incubator with an atmosphere of 5% CO2, 95% air at 37°C. Different concentrations of Cerium oxide nanoparticles were added to the cultures before exposure to various concentrations of H₂O₂. Cells were collected after trypsin digestion and Cell death was determined by flow cytometry using an Annexin V-FITC kit (Beckman Coulter Inc, Fullerton, CA) according to the manufacturer’s instructions.

Results:: No cytotoxicity was detected at any concentration of Nanoceria particles tested up to 10 nM. There was a clear dose-dependent effect of nanoparticles against 200 µM concentration of H₂O_2. Treatment with a 10nM suspension of Nanoceria particles demonstrated the best protective effect. Interestingly, the 10 nM nanoparticle treatment also effectively inhibited 400 and 600 µM H₂O₂-induced RPE cell death.

Conclusions:: Our data demonstrate that Cerium Oxide nanoparticles, in a dose-dependent manner, significantly decrease the death of RPE cells induced by H₂O₂. This indicates that Cerium oxide nanoparticles may be useful in protecting RPE cells in vivo which might delay or prevent the development of age-related macular degeneration.

Keywords: retinal pigment epithelium • oxidation/oxidative or free radical damage • age-related macular degeneration