Effects of Solar Particle Event-Like Proton Radiation and/or Simulated Microgravity on Circulating Mouse Blood Cells

Ana Lilian Romero-Weaver, Liyong Lin, Alejandro Carabe-Fernandez, Ann R Kennedy


Astronauts traveling in space missions outside of low earth orbit will be exposed for longer times to a microgravity environment. In addition, the increased travel time involved in exploration class missions will result in higher risks of exposure to significant doses of solar particle event (SPE) radiation. Both conditions could significantly affect the number of circulating blood cells. Therefore, it is critical to determine the combined effects of exposure to both microgravity and SPE radiation. Thus, the purpose of the present study was to assess the risk that astronauts would have in the event of exposure to SPE radiation by evaluating the effects of SPE-like proton radiation and/or simulated microgravity on circulating blood cells using mouse as the model system. The results indicate that exposure to HU alone caused minimal or no significant changes in mouse circulating blood cell numbers. The exposure of mice to the combined treatment with SPE-like proton radiation and HU caused a significant decrease in the number of circulating lymphocytes, granulocytes and platelets which was similar to the decrease caused by exposure to SPE-like proton radiation alone. The reduced numbers of circulating lymphocytes, granulocytes and platelets resulting from the combined exposure to SPE-like proton radiation and HU indicate that astronauts participating in exploration class missions are at higher risks of developing infections and thrombotic diseases; thus, countermeasures are necessary for these biological endpoints.


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