title: Lutein and zeaxanthin supplementation reduces H2O2-induced oxidative damage in human lens epithelial cells.
abstract: OBJECTIVE
  Epidemiological studies suggest that dietary intake of lutein and zeaxanthin is inversely related to the risk for senile cataract. The objectives of this work were to investigate the mechanisms by which these nutrients provide anti-cataract effects. We evaluated their modulation of oxidative damage in human lens epithelial cells (HLEC) and their interaction with intracellular glutathione (GSH).
  
  
  METHODS
  Subconfluent HLEC were pre-incubated with or without 5 µM lutein, zeaxanthin, or α-tocopherol for 48 h and then exposed to 100 µM H(2)O(2) for 1 h. Levels of protein carbonyls in the cells were measured by western-blotting analysis following reaction with 2,4-dinitrophenylhydrazine (DNPH). Levels of malondialdehyde (MDA), reduced glutathione (GSH) and oxidized glutathione (GSSG) were measured by an HPLC system. DNA damage was assessed using comet assays. Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay.
  
  
  RESULTS
  In the absence of H(2)O(2), HLEC had very low levels of protein carbonyl and MDA. Supplementation with lutein, zeaxanthin, or α-tocopherol to the unstressed HLEC had no detectable effects on levels of oxidized proteins and lipid in the cells. Exposure of HLEC to H(2)O(2) significantly increased levels of oxidized proteins, lipid peroxidation, and DNA damage. Pre-incubation with lutein, zeaxanthin, or α-tocopherol dramatically reduced the levels of H(2)O(2) -induced protein carbonyl, MDA, and DNA damage in HLEC. The protective effects of lutein, zeaxanthin, and α-tocopherol against protein oxidation, lipid peroxidation, and DNA damage were comparable. Supplementation with lutein, zeaxanthin, or α-tocopherol increased GSH levels and GSH:GSSG ratio, particularly in response to oxidative stress. Depletion of GSH resulted in significant increase in susceptibility to H(2)O(2)-induced cell death. Supplementation with α-tocopherol, but not lutein or zeaxanthin, can partially restore the resistance of GSH-depleted cells to H(2)O(2).
  
  
  CONCLUSIONS
  These data indicate that lutein or zeaxanthin supplementation protects lens protein, lipid, and DNA from oxidative damage and improves intracellular redox status upon oxidative stress. The protective effects are comparable to that of α-tocopherol, except that lutein and zeaxanthin cannot compensate for GSH depletion. The data imply that sufficient intake of lutein and zeaxanthin may reduce the risk for senile cataract via protecting the lens from oxidative damage.
authors.affiliation: State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, China.
authors.forename: Shasha
authors.initials: S
authors.lastname: Gao
authors.forename: Tingyu
authors.initials: T
authors.lastname: Qin
authors.forename: Zhenzhen
authors.initials: Z
authors.lastname: Liu
authors.forename: Maria Andrea
authors.initials: MA
authors.lastname: Caceres
authors.forename: Carlos F
authors.initials: CF
authors.lastname: Ronchi
authors.forename: C-Y Oliver
authors.initials: CY
authors.lastname: Chen
authors.forename: Kyung-Jin
authors.initials: KJ
authors.lastname: Yeum
authors.forename: Allen
authors.initials: A
authors.lastname: Taylor
authors.forename: Jeffery B
authors.initials: JB
authors.lastname: Blumberg
authors.forename: Yizhi
authors.initials: Y
authors.lastname: Liu
authors.forename: Fu
authors.initials: F
authors.lastname: Shang
mesh_terms: D015153:Blotting, Western; D002386:Cataract / Q000517:prevention & control*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D020552:Comet Assay; D004249:DNA Damage / Q000187:drug effects; D019587:Dietary Supplements; D004847:Epithelial Cells / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D005978:Glutathione / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000009:adverse effects; D007908:Lens, Crystalline / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D014975:Lutein / Q000494:pharmacology*; D008315:Malondialdehyde / Q000032:analysis; D010084:Oxidation-Reduction / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects; D050050:Protein Carbonylation / Q000187:drug effects; D024341:Xanthophylls / Q000494:pharmacology*; D065146:Zeaxanthins; D024502:alpha-Tocopherol / Q000494:pharmacology*
chemical_list: D024341:Xanthophylls; D065146:Zeaxanthins; D008315:Malondialdehyde; D006861:Hydrogen Peroxide; D005978:Glutathione; D024502:alpha-Tocopherol; D014975:Lutein