Dose-response relationship for alpha-tocopherol prevention of ultraviolet radiation induced cataract in rat
2011 (English)In: Experimental Eye Research, ISSN 0014-4835, E-ISSN 1096-0007, Vol. 93, no 1, 91-97 p.Article in journal (Refereed) Published
The purpose of this study is to establish the dose response relationship for alpha-tocopherol protection of ultraviolet radiation (UVR) induced cataract in the rat. Four groups of 20 six-week-old albino Sprague Dawley rats received 5, 25, 50, and 100 IU/day alpha-tocopherol, whilst another group of 20 rats without any alpha-tocopherol feeding was the control group. After 4 weeks of feeding, each rat was unilaterally exposed to 8 kJ/m(2) UVR-300 nm for 15 min. At 1 week after exposure, the rats were sacrificed and lens light scattering was measured quantitatively. Lens total reduced (GSH) and oxidized (GSSG) glutathione; glutathione reductase (GR) and peroxidase (GPx) were determined spectrophotometrically. The UVR-exposed lenses in the alpha-tocopherol fed groups developed superficial cataract, whereas lenses in the control group developed cortical and equatorial opacities. Light scattering in lenses from the alpha-tocopherol-supplemented rats was lower than in lenses from the control group. The difference of light scattering between the exposed and contralateral non-exposed lens decreased with increasing doses of alpha-tocopherol to an asymptote level. UVR-exposure caused a significant depletion of lens GSH in rats without or at low alpha-tocopherol supplementation. The depletion of GSH became less with higher alpha-tocopherol supplementation. There was no detectable difference in lens GSSG, GR or GPx at any level of alpha-tocopherol supplementation. Orally administered alpha-tocopherol dose dependently protects against UVR-induced cataract. The protection is associated with an alpha-tocopherol dose-dependent GSH depletion secondary to UVR exposure. UVR-induced light scattering only occurs if the GSH depletion exceeds a threshold.
Place, publisher, year, edition, pages
2011. Vol. 93, no 1, 91-97 p.
forward light scattering, lens, cataract, ultraviolet radiation, alpha-tocopherol, dose-dependent
IdentifiersURN: urn:nbn:se:uu:diva-156961DOI: 10.1016/j.exer.2011.05.002ISI: 000293042200011PubMedID: 21620831OAI: oai:DiVA.org:uu-156961DiVA: diva2:435822
FunderSwedish Research Council, K2008-63X-15035-05-2