|RABIN, BERNARD - University Of Maryland|
|POULOSE, SHIBU - Jean Mayer Human Nutrition Research Center On Aging At Tufts University|
|MILLER, MARSHALL - Duke University|
|BIELINSKI, DONNA - Jean Mayer Human Nutrition Research Center On Aging At Tufts University|
|HAWKINS, ELIZABETH - University Of Maryland|
|LARSEN, ALISON - University Of Maryland|
|SPADAFORA, CHRISTINA - University Of Maryland|
|ZOLNEROWICH, NICHOLAS - University Of Maryland|
|DELL'ACQUA, LORRAINE ANASTA - University Of Maryland|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/30/2018
Publication Date: 7/14/2018
Citation: Rabin, B., Poulose, S.M., Miller, M.M., Bielinski, D.F., Hawkins, E.M., Larsen, A., Spadafora, C., Zolnerowich, N.N., Dell'Acqua, L.C., Shukitt Hale, B. 2018. Changes in neuronal function and cognitive performance following exposure to very low doses of helium particles [abstract]. COSPAR 2018 Scientific Assembly Abstracts #F2.1-0013-18, p. 1904.
Technical Abstract: Helium (4He) particles will form a significant portion of the radiation environment on exploratory class missions, such as a mission to Mars. Because the linear energy transfer (LET) of 4He particles is low (approx. 0.9 keV/µm), they might be expected to produce less damage to neuronal tissue as they pass through the brain. As such, they might be expected to have little effect on cognitive performance. Sprague-Dawley rats weighing between 200-225 g were given either head-only or whole-body exposures to 4He particles (1000 MeV/n) at doses ranging from 0.01 to 0.5 cGy. Following exposure, the brains were removed from a subset of the rats for analysis of oxidative stress by measuring NADPH oxidase (NOX2) expression. Measurements were also made of phosphorylated-cyclic AMP (cAMP)-responsive element-binding protein (CREB) and nuclear factor E2-related factor 2 (Nrf2). The remaining rats (n = 10/dose) were shipped to University of Maryland, Baltimore County (UMBC) for behavioral testing, including elevated plus maze (baseline anxiety); novel object and novel spatial recognition (learning and memory); and operant responding on an ascending fixed-ratio schedule (motivation to work for reward). The results indicated that changes in behavioral endpoints could be observed following exposures to 4He particles at doses as low as 0.01 to 0.025 cGy. Differences in neurochemical endpoints were observed following exposure to doses as low as 0.05 cGy (the lowest dose tested). There were no significant differences between head-only and whole-body exposures on behavioral performance. Analyses of the neurochemical data suggest that whole body exposures may not have been as effective in producing changes in neuronal functioning as were head-only exposures. Because 4He particles will constitute a significant fraction of the radiation dose to which astronauts will be exposed, the present results suggest the possibility that astronauts on exploratory class missions may be at a greater risk for HZE-induced cognitive deficits than anticipated.