Abstract
Purpose: :
To test the protective effects of quercetin against induced oxidative stress in human RPE cells in vitro.
Methods: :
Human retinal pigment epithelial (hRPE) cells were subjected to oxidative stress induced by two reactive oxygen species cytotoxins (0.3 mM H2O2 or 0.1 mM tertiary butyl hydroperoxide [TBOOH]). Quantity of viable cells was measured using the MTT assay. To determine the protective antioxidant effect of quercetin some hRPE cells were pretreated with 10 -300 µM quercetin. Cells cultured without quercetin or reactive oxygen species (ROS) were used as controls. All tests were run in triplicate.
Results: :
Quercetin was not cytotoxic to hRPE cells in concentrations of 10 to 100 µM and this concentration range was chosen to measure protective effect against the two oxidants. H2O2 at 0.3 mM decreased viable cells to 46% of the control (without H2O2). Viable cells cultured with 10, 30 and 100 uM quercetin and H2O2 were 109%, 117% and 154% of cells cultured with H2O2 but without quercetin. In H2O2 treated group, the difference between cells cultured with and without quercetin was statistically significant (0.05>P>0.01 at 30 µM and P < 0.01 at 100 µM). TBOOH at 0.1 mM decreased viable cells to 41% of the control (without TBOOH). Quantity of viable cells cultured with 10, 30 and 100 µM quercetin was 115%, 175% and 205% of cells cultured with TBOOH but without quercetin. In TBOOH group,the difference between cells cultured with and without quercetin was statistically significant (P < 0.01 at 30 and100 µM).
Conclusions: :
Quercetin at concentrations of 30 -100 µm had a dose dependent protective effect against the oxidative damage of human RPE cells induced by H2O2 and TBOOH. Human retinal epithelial cells are constantly exposed to environmental hazards, such as sunlight, smog and cigarette smoke that results in the formation of reactive oxygen species which damage the retinal cells. Quercetin is a non-toxic antioxidant found in apples and berries which may protect and preserve the function of the human retinal epithelial cells against such damage.
Keywords: retinal pigment epithelium • antioxidants • oxidation/oxidative or free radical damage