Late Effects of 1H Irradiation on Hippocampal Physiology

Publication date: Available online 15 March 2018 Source:Life Sciences in Space Research Author(s): Frederico Kiffer, Alexis K. Howe, Hannah Carr, Jing Wang, Tyler Alexander, Julie E. Anderson, Thomas Groves, John W. Seawright, Vijayalakshmi Sridharan, Gwendolyn Carter, Marjan Boerma, Antiño R. Allen NASA's Missions to Mars and beyond will expose flight crews to potentially dangerous levels of charged-particle radiation. Of all charged nuclei, 1H is the most abundant charged particle in both the galactic cosmic ray (GCR) and solar particle event (SPE) spectra. There are currently no functional spacecraft shielding materials that are able to mitigate the charged-particle radiation encountered in space. Recent studies have demonstrated cognitive injuries due to high-dose 1H exposures in rodents. Our study investigated the effects of 1H irradiation on neuronal morphology in the hippocampus of adult male mice. 6-month-old mice received whole-body exposure to 1H at 0.5 and 1Gy (150 MeV/n; 0.35-0.55Gy/min) at NASA's Space Radiation Laboratory in Upton, NY. At 9-months post-irradiation, we tested each animal's open-field exploratory performance. After sacrifice, we dissected the brains along the midsagittal plane, and then either fixed or dissected further and snap-froze them. Our data showed that exposure to 0.5 Gy or 1 Gy 1H significantly increased animals’ anxiety behavior in open-field testing. Our micromorphometric analyses revealed significant decreases in mush...
Source: Life Sciences in Space Research - Category: Biology Source Type: research