High dietary iron increases oxidative stress and radiosensitivity in the rat retina and vasculature after exposure to fractionated gamma radiation.

Autor:	Theriot CA; Department of Preventive Medicine and Community Health, University of Texas Medical Branch, Galveston, TX, USA., Westby CM; Universities Space Research Association, Division of Space Life Sciences, Houston, TX, USA., Morgan JLL; Oak Ridge Associated Universities, NASA Johnson Space Center, Houston, TX, USA., Zwart SR; Universities Space Research Association, Division of Space Life Sciences, Houston, TX, USA., Zanello SB; Universities Space Research Association, Division of Space Life Sciences, Houston, TX, USA.
Jazyk:	angličtina
Zdroj:	NPJ microgravity [NPJ Microgravity] 2016 May 05; Vol. 2, pp. 16014. Date of Electronic Publication: 2016 May 05 (Print Publication: 2016).
DOI:	10.1038/npjmgrav.2016.14
Abstrakt:	Radiation exposure in combination with other space environmental factors including microgravity, nutritional status, and deconditioning is a concern for long-duration space exploration missions. Astronauts experience altered iron homeostasis due to adaptations to microgravity and an iron-rich food system. Iron intake reaches three to six times the recommended daily allowance due to the use of fortified foods on the International Space Station. Iron is associated with certain optic neuropathies and can potentiate oxidative stress. This study examined the response of eye and vascular tissue to gamma radiation exposure (3 Gy fractionated at 37.5 cGy per day every other day for 8 fractions) in rats fed an adequate-iron diet or a high-iron diet. Twelve-week-old Sprague-Dawley rats were assigned to one of four experimental groups: adequate-iron diet/no radiation (CON), high-iron diet/no radiation (IRON), adequate-iron diet/radiation (RAD), and high-iron diet/radiation (IRON+RAD). Animals were maintained on the corresponding iron diet for 2 weeks before radiation exposure. As previously published, the high-iron diet resulted in elevated blood and liver iron levels. Dietary iron overload altered the radiation response observed in serum analytes, as evidenced by a significant increase in catalase levels and smaller decrease in glutathione peroxidase and total antioxidant capacity levels. 8-OHdG immunostaining, showed increased intensity in the retina after radiation exposure. Gene expression profiles of retinal and aortic vascular samples suggested an interaction between the response to radiation and high dietary iron. This study suggests that the combination of gamma radiation and high dietary iron has deleterious effects on retinal and vascular health and physiology. Competing Interests: S.B.Z. and S.R.Z. hold employment at Universities Space Research Association (USRA). C.A.T. receives compensation from the University of Texas Medical Branch and J.L.L.M. was a postdoctoral fellow at NASA-JSC at the time this work was conducted. C.M.W. was a scientist with USRA at the time of conduction of the study.
Databáze:	MEDLINE
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