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

Radiation exposure or astronaut food may explain visual problems found in more than half the astronauts returning from long space flights. Susana Zanello from the Universities Space Research Association and U.S. colleagues exposed rats to gamma radiation, high-iron diets, or both – mimicking the effects of spaceflight and the astronaut diet – and examined resulting changes in eye and blood vessel tissues. Compared to controls, the high-iron-diet only and radiation-only groups had more DNA damage in the eye, along with systemic gene expression changes. However, when the two treatments were combined, high-iron diets attenuated radiation-induced DNA damage in the eye. This study provides preliminary evidence of a complex interaction between blood iron levels and radiation damage in eye disease, demanding further research before astronauts embark on further long-term space voyages like a manned mission to Mars.