Alterations in synaptic density and myelination in response to exposure to high-energy charged particles

Dara L. Dickstein, Ronan Talty, Erin Bresnahan, Merina Varghese, Bayley Perry, William G.M. Janssen, Allison Sowa, Erich Giedzinski, Lauren Apodaca, Janet Baulch, Munjal Acharya, Vipan Parihar, Charles L. Limoli

Research output: Contribution to journalArticlepeer-review

19 Scopus citations

Abstract

High-energy charged particles are considered particularly hazardous components of the space radiation environment. Such particles include fully ionized energetic nuclei of helium, silicon, and oxygen, among others. Exposure to charged particles causes reactive oxygen species production, which has been shown to result in neuronal dysfunction and myelin degeneration. Here we demonstrate that mice exposed to high-energy charged particles exhibited alterations in dendritic spine density in the hippocampus, with a significant decrease of thin spines in mice exposed to helium, oxygen, and silicon, compared to sham-irradiated controls. Electron microscopy confirmed these findings and revealed a significant decrease in overall synapse density and in nonperforated synapse density, with helium and silicon exhibiting more detrimental effects than oxygen. Degeneration of myelin was also evident in exposed mice with significant changes in the percentage of myelinated axons and g-ratios. Our data demonstrate that exposure to all types of high-energy charged particles have a detrimental effect, with helium and silicon having more synaptotoxic effects than oxygen. These results have important implications for the integrity of the central nervous system and the cognitive health of astronauts after prolonged periods of space exploration.

Original languageEnglish
Pages (from-to)2845-2855
Number of pages11
JournalJournal of Comparative Neurology
Volume526
Issue number17
DOIs
StatePublished - 1 Dec 2018

Keywords

  • charged particles
  • dendritic spines
  • myelin
  • synapses

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