title: Blue light-induced oxidative stress in human corneal epithelial cells: protective effects of ethanol extracts of various medicinal plant mixtures.
abstract: OBJECTIVE
  To investigate the effects of visible light on human corneal epithelial cells and the impact of natural antioxidants on oxidative stress produced by overexposure to light.
  
  
  METHODS
  Light-emitting diodes with various wavelengths (410-830 nm) were used to irradiate human corneal epithelial cells, and cell viability was assessed. The production of reactive oxygen species (ROS) was analyzed using 2',7'-dichlorodihydrofluorescein diacetate (DCF-DA). Ethyl alcohol (EtOH) extracts were prepared from mixtures of medicinal plants. After application of the EtOH extracts, the free radical scavenging activity was measured using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The induction of antioxidant enzymes including heme oxygenase-1 (HO-1), peroxiredoxin-1 (Prx-1), catalase (CAT), and superoxide dismutase-2 (SOD-2) by the extracts was evaluated by reverse transcription-polymerase chain reaction and Western blotting. The ability of the extracts to inhibit ROS was also analyzed using DCF-DA.
  
  
  RESULTS
  The viability of corneal epithelial cells was diminished after irradiation of blue light (above 10 J at 410 nm and 50 J at 480 nm). Reactive oxygen species production was induced by irradiation at 410 and 480 nm at doses of 5 J/cm(2) and higher. Ethyl alcohol extracts had potent radical scavenging activity. Application of the extracts not only increased the expression of HO-1, Prx-1, CAT, and SOD-2, but it also attenuated the ROS production induced by blue light in a dose-dependent manner.
  
  
  CONCLUSIONS
  Overexposure to blue light (410-480 nm) may have a harmful effect on human corneal epithelial cells compared with other visible light wavelengths. Medicinal plant extracts can have potent protective effects on blue light-induced oxidative stress.
authors.affiliation: Department of Dermatology, Chonnam National University Medical School and Hospital, Gwangju, Korea.
authors.forename: Jee-Bum
authors.initials: JB
authors.lastname: Lee
authors.affiliation: Department of Dermatology, Chonnam National University Medical School and Hospital, Gwangju, Korea.
authors.forename: Soo-Hyun
authors.initials: SH
authors.lastname: Kim
authors.affiliation: Department of Dermatology, Chonnam National University Medical School and Hospital, Gwangju, Korea.
authors.forename: Seung-Chul
authors.initials: SC
authors.lastname: Lee
authors.affiliation: Department of Chemical Engineering, Sunchon National University, Chonnam, Korea.
authors.forename: Hee-Gu
authors.initials: HG
authors.lastname: Kim
authors.affiliation: Department of Chemical Engineering, Sunchon National University, Chonnam, Korea.
authors.forename: Ho-Geun
authors.initials: HG
authors.lastname: Ahn
authors.affiliation: Department of Ophthalmology, Chonnam National University Medical School and Hospital and Center for Creative Biomedical Scientists at Chonnam National University, Gwangju, Korea.
authors.forename: Zhengri
authors.initials: Z
authors.lastname: Li
authors.affiliation: Department of Ophthalmology, Chonnam National University Medical School and Hospital and Center for Creative Biomedical Scientists at Chonnam National University, Gwangju, Korea.
authors.forename: Kyung Chul
authors.initials: KC
authors.lastname: Yoon
mesh_terms: D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004307:Dose-Response Relationship, Radiation; D019573:Epithelium, Corneal / Q000187:drug effects / Q000378:metabolism* / Q000528:radiation effects; D000431:Ethanol / Q000494:pharmacology*; D006801:Humans; D008027:Light / Q000009:adverse effects*; D018384:Oxidative Stress / Q000187:drug effects* / Q000528:radiation effects; D010936:Plant Extracts / Q000494:pharmacology*; D010946:Plants, Medicinal; D011832:Radiation Injuries / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D017382:Reactive Oxygen Species / Q000378:metabolism; D012997:Solvents / Q000494:pharmacology
chemical_list: D010936:Plant Extracts; D017382:Reactive Oxygen Species; D012997:Solvents; D000431:Ethanol
keywords: corneal epithelial cells; light emitting diode; medicinal plants; oxidative stress; reactive oxygen species; visible light