title: Green tea catechins are potent anti-oxidants that ameliorate sodium iodate-induced retinal degeneration in rats.
abstract: Green tea extracts exhibit anti-oxidative and anti-inflammatory actions in different disease conditions. We hypothesized that green tea extract and its catechin constituents ameliorate sodium iodate-induced retinal degeneration in rats by counteracting oxidative stress. In this study, adult Sprague-Dawley rats were intravenously injected with a single dose of sodium iodate. Green tea extract (GTE; Theaphenon-E) or combinations of its catechin constituents, including (-)-epigallocatechin gallate (EGCG), were administered intra-gastrically before injection. Live imaging analysis using confocal scanning laser ophthalmoscopy and spectral-domain optical coherence tomography showed a progressive increase of degenerating profile across the retinal surface and decrease in thickness of outer nuclear layer (ONL) at Day-14 of post-injection. These lesions were significantly ameliorated by Theaphenon-E and catechin combinations with EGCG. Catechins with exclusion of EGCG did not show obvious protective effect. Histological analyses confirmed that Theaphenon-E and catechins containing EGCG protect the retina by reducing ONL disruption. Retinal protective effects were associated with reduced expression of superoxide dismutase, glutathione peroxidase and caspase-3, and suppression of 8-iso-Prostaglandin F2α generation in the retina. In summary, GTE and its catechin constituents are potent anti-oxidants that offer neuroprotection to the outer retinal degeneration after sodium iodate insult, among which EGCG is the most active constituent.
authors.affiliation: Department of Ophthalmology &Visual Sciences, The Chinese University of Hong Kong, Hong Kong.|Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, China.
authors.forename: Yaping
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Ophthalmology &Visual Sciences, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Yong Jie
authors.initials: YJ
authors.lastname: Qin
authors.affiliation: Department of Ophthalmology &Visual Sciences, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Yolanda W Y
authors.initials: YW
authors.lastname: Yip
authors.affiliation: Department of Ophthalmology &Visual Sciences, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Kwok Ping
authors.initials: KP
authors.lastname: Chan
authors.affiliation: Department of Ophthalmology &Visual Sciences, The Chinese University of Hong Kong, Hong Kong.|Department of Obstetrics &Gynaecology, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Kai On
authors.initials: KO
authors.lastname: Chu
authors.affiliation: Department of Ophthalmology &Visual Sciences, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Wai Kit
authors.initials: WK
authors.lastname: Chu
authors.affiliation: Department of Ophthalmology &Visual Sciences, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Tsz Kin
authors.initials: TK
authors.lastname: Ng
authors.affiliation: Department of Ophthalmology &Visual Sciences, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Chi Pui
authors.initials: CP
authors.lastname: Pang
authors.affiliation: School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Hong Kong.
authors.forename: Sun On
authors.initials: SO
authors.lastname: Chan
mesh_terms: D000284:Administration, Oral; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D002392:Catechin / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology*; D015237:Dinoprost / Q000031:analogs & derivatives / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D007452:Iodates / Q000633:toxicity; D009887:Ophthalmoscopy / Q000379:methods; D018384:Oxidative Stress / Q000187:drug effects; D017207:Rats, Sprague-Dawley; D012162:Retinal Degeneration / Q000139:chemically induced / Q000188:drug therapy* / Q000473:pathology; D055213:Retinal Pigment Epithelium / Q000187:drug effects / Q000473:pathology; D013662:Tea / Q000737:chemistry*
chemical_list: D000975:Antioxidants; D007452:Iodates; D013662:Tea; C075750:8-epi-prostaglandin F2alpha; D002392:Catechin; D015237:Dinoprost; C045651:epigallocatechin gallate; C032285:sodium iodate