Just 13 days in space may be enough to cause profound changes in eye structure and gene expression, report researchers from Houston Methodist, NASA Johnson Space Center, and two other institutions in the October 2013 issue of Gravitational and Space Research.
The study, which looked at how low gravity and radiation and oxidative damage impacts mice, is the first to examine eye-related gene expression and cell behavior after spaceflight.
“We found many changes in the expression of genes that help cells cope with oxidative stress in the retina, possibly caused by radiation exposure,” said Houston Methodist pathologist Patricia Chévez-Barrios, M.D., the study’s principal investigator. “These changes were partially reversible upon return to Earth. We also saw optic nerve changes consistent with mechanical injury, but these changes did not resolve. And we saw changes in the expression of DNA damage repair genes and in apoptotic pathways, which help the body destroy cells that are irreparably damaged.”
Since 2001, studies have shown astronauts are at increased risk of developing eye problems, like premature age-related macular degeneration. Experts suspect the cause is low gravity, heightened exposure to solar radiation, or a combination of the two.