title: Epigallocatechin gallate eye drops protect against ultraviolet B-induced corneal oxidative damage in mice.
abstract: OBJECTIVE
  Ultraviolet B (UVB) radiation from sunlight is a known risk factor for human corneal injury. The aim of the present study was to investigate the protective effects of green tea polyphenol epigallocatechin gallate (EGCG) on UVB radiation-induced corneal oxidative damage in male imprinting control region (ICR) mice.
  
  
  METHODS
  Corneal oxidative damage was induced by exposure to UVB radiation at 560 μW/cm(2). The animals received 0%, 0.1%, and 0.01% EGCG eye drops at a 5 mg/ml dose, twice daily for 8 days. Corneal surface damage was graded according to smoothness and the extent of lissamine green staining. Corneal glutathione (GSH), thiobarbituric acid-reactive substances (TBARS), and protein carbonyl levels, as well as superoxide dismutase (SOD), catalase, glutathione peroxidase (GSH-Px), and glutathione reductase (GSH-Rd) activity in the cornea, were measured to monitor corneal injury.
  
  
  RESULTS
  UVB radiation caused significant damage to the corneas, including apparent corneal ulceration and severe epithelial exfoliation, leading to a decrease in SOD, catalase, GSH-Px, GSH-Rd, and GSH activity in the cornea. However, the corneal TBARS and protein carbonyls increased compared with the control group. Treatment with EGCG eye drops significantly (p<0.05) ameliorated corneal damage, increased SOD, catalase, GSH-Px, GSH-Rd, and GSH activity, and decreased the TBARS and protein carbonyls in the corneas compared with the UVB-treated group.
  
  
  CONCLUSIONS
  EGCG eye drops exhibit potent protective effects on UVB radiation-induced corneal oxidative damage in mice, likely due to the increase in antioxidant defense system activity and the inhibition of lipid peroxidation and protein oxidation.
authors: Institute of Medicine, College of Medicine, Chung Shan Medical University, Taichung City, Taiwan, ROC.
authors: Mu-Hsin
authors: MH
authors: Chen
authors: Department of Biotechnology, TransWorld University, Douliu City, Taiwan, ROC.
authors: Chia-Fang
authors: CF
authors: Tsai
authors: School of Occupational Safety and Health, Chung Shan Medical University, Taichung City, Taiwan, ROC ; Department of Ophthalmology, Chung Shan Medical University Hospital, Taichung City, Taiwan, ROC.
authors: Yu-Wen
authors: YW
authors: Hsu
authors: Institute of Medicine, College of Medicine, Chung Shan Medical University, Taichung City, Taiwan, ROC ; Department of Ophthalmology, Chung Shan Medical University Hospital, Taichung City, Taiwan, ROC.
authors: Fung-Jou
authors: FJ
authors: Lu
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000378:metabolism; D002374:Catalase / Q000378:metabolism; D002392:Catechin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000494:pharmacology; D003315:Cornea / Q000187:drug effects* / Q000201:enzymology / Q000473:pathology* / Q000528:radiation effects; D005978:Glutathione / Q000378:metabolism; D005979:Glutathione Peroxidase / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D006801:Humans; D008086:Lissamine Green Dyes / Q000378:metabolism; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009883:Ophthalmic Solutions / Q000008:administration & dosage / Q000494:pharmacology*; D018384:Oxidative Stress / Q000187:drug effects* / Q000528:radiation effects*; D020011:Protective Agents / Q000008:administration & dosage / Q000494:pharmacology; D050050:Protein Carbonylation / Q000187:drug effects / Q000528:radiation effects; D013482:Superoxide Dismutase / Q000378:metabolism; D017392:Thiobarbituric Acid Reactive Substances / Q000378:metabolism; D014466:Ultraviolet Rays
chemical_list: D000975:Antioxidants; D008086:Lissamine Green Dyes; D009883:Ophthalmic Solutions; D020011:Protective Agents; D017392:Thiobarbituric Acid Reactive Substances; D002392:Catechin; C045651:epigallocatechin gallate; D002374:Catalase; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase; D005978:Glutathione