Protective Effectof Tea Polyphenols against Oxidative Injury on Human Retinal Pigment EpithelialCells

To observe theprotective effect of tea polyphenols on oxidative damage of human retinalpigment epithelial cells. In an in vitro experiment, this study appliedhydrogen peroxide (H₂O₂) solution to induce oxidative injuryon human retinal pigment epithelial (hRPE-19) cells. Tea polyphenols (TP) werefirstly tested to confirm that, at a concentration below 16mg·mL^-1,it inflicted no proliferation and/or toxicological effects on the cells.Subsequently, in 5 treatments, TP were applied on the cells in vitro todetermine the resulting cellular viability, superoxide dismutase (SOD) andmalondialdehyde (MDA) contents as well as apoptosis rate. It was found that an oxidativedamage with a reduced intracellular SOD activity and an elevated MDA content onthe hRPE-19 cells could best be identified by allowing 24h for a 500μmol·L^-1 H₂O₂ solution to act upon the cells. The TP applicationat 8mg·mL^-1 level appeared optimal to exert stress releasing shownby the selected indicators after the imposed H₂O₂ treatment. Hence, it was postulated that TP might be capable of delaying theage-related macular degeneration (ARMD) and other retinal diseases in human.