Xanthophylls protect against induced oxidation in cultured human retinal pigment epithelial cells

Lutein and zeaxanthin are dietary carotenoids which accumulate in human retina, including the retinal pigment epithelial (RPE) cells. Oxidative damage of RPE cells is involved in the pathogenesis age related macular degeneration (AMD). The purpose of this study was to evaluate the potential protective effect of lutein and zeaxanthin against hydrogen peroxide induced oxidative stress in cultured human RPE cells. Human D407 RPE cells were pretreated with lutein and zeaxanthin (10 μM) for 24 h, and exposed for 1 h to 500 μM hydrogen peroxide. Cell viability, reactive oxygen species (ROS), the lipid peroxidation and the activity of antioxidant enzymes were determined in basal and oxidative stress conditions. Lutein and zeaxanthin pretreatment protected RPE cells against hydrogen peroxide induced cytoxicity, and inhibited the intracellular ROS generation and lipid peroxidation. Xanthophylls induced a significant increase of superoxide dismutase and glutathione peroxidase activity and of the level of reduced glutathione, but did not significantly modify the catalase activity. These results suggest that lutein and zeaxanthin supplementation can contribute to the prevention of age-related macular degeneration, not only by increasing the macular pigment density, but also by protecting retinal pigment epithelium against oxidative stress.