Late Effects of 1H + 16O on Short-Term and Object Memory, Hippocampal Dendritic Morphology and Mutagenesis

摘要: The space extending beyond Earth's magnetosphere is subject to a complex field of high-energy charged nuclei, which are capable traversing spacecraft shielding and human tissues, inducing dense ionization events. central nervous system major area concern for astronauts who will be exposed the deep-space radiation environment on mission Mars, as charged-particle has been shown elicit changes dendritic arbor within hippocampus rodents, related cognitive-behavioral deficits. We 6-month-old male mice whole-body 1H (0.5 Gy; 150 MeV/n; 18-19 cGy/minute) an hour later 16O (0.1Gy; 600 18-33 Gy/min) at NASA's Space Radiation Laboratory galactic cosmic ray-relevant model. Animals were housed with bedding provides cognitive enrichment. Mice tested behavior 9 months after exposure elucidate late effects. induced significant deficits in novel object recognition short-term spatial memory (Y-maze). Additionally, we observed opposing morphological differences between mature granular pyramidal neurons throughout hippocampus, increased length dorsal dentate gyrus reduced complexity CA1 subregion hippocampus. Dendritic spine analyses revealed severe reduction mushroom density irradiated animals. Finally, detected no general effect single-nucleotide polymorphisms immediate early genes, genes involved inflammation but found higher variant allele frequency antioxidants thioredoxin reductase 2 3 loci.