|RABIN, BERNARD - University Of Maryland|
|MILLER, MARSHALL - Former ARS Employee|
|LARSEN, ALISON - University Of Maryland|
|SPADAFORA, CHRISTINA - University Of Maryland|
|ZOLNEROWICH, NICHOLAS - University Of Maryland|
|DELL'ACQUA, LORRAINE - University Of Maryland|
Submitted to: Life Sciences in Space Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 7/9/2019
Publication Date: 7/16/2019
Citation: Rabin, B.M., Miller, M.G., Larsen, A., Spadafora, C., Zolnerowich, N.N., Dell'Acqua, L.A., Shukitt Hale, B. 2019. Effects of exposure to 12C and 4He particles on cognitive performance of intact and ovariectomized female rats. Life Sciences in Space Research. 22:47-54. https://doi.org/10.1016/j.lssr.2019.07.005.
Interpretive Summary: Exposure to radiation in outer space can affect the brain and disrupt memory function. It is possible that female astronauts may be less affected by radiation than male astronauts, because of the hormone estrogen, which can have protective effects on the brain. To evaluate this, female rats, whose ovaries were either removed or not, were given implants containing either supplemental estrogen or a control substance. Following exposure to radiation, the rats underwent memory tests. RESULTS indicated that radiation did not disrupt brain performance in the female rats with intact ovaries. Rats without ovaries showed brain performance that was disrupted by radiation; however, rather than being protective, estrogen implants in these subjects exacerbated the disruptive effects of radiation. CONCLUSIONS are that supplemental estrogen does not appear to be protecting the brain following exposure to radiation but that female rats with intact ovaries may be less responsive overall to the damaging effects of space radiation, compared to male rats.
Technical Abstract: Exposure to the types of radiation encountered outside the magnetic field of the earth can disrupt cognitive performance. Exploratory class missions to other planets will include both male and female astronauts. Because estrogen can function as a neuroprotectant, it is possible that female astronauts may be less affected by exposure to space radiation than male astronauts. To evaluate the effectiveness of estrogen to protect against the disruption of cognitive performance by exposure to space radiation, intact and ovariectomized female rats with estradiol or vehicle implants were tested on novel object performance and operant responding on an ascending fixed-ratio reinforcement schedule following exposure to 12C (290 MeV/n) or 4He particles (300 MeV/n). The results indicated that exposure to carbon or helium particles did not disrupt cognitive performance in the intact rats. Estradiol implants in the ovariectomized subjects exacerbated the disruptive effects of space radiation on operant performance. Although estrogen does not appear to function as a neuroprotectant following exposure to space radiation, the present data suggest that intact females may be less responsive to the deleterious effects of exposure to space radiation on cognitive performance, possibly due to the effects of estrogen on cognitive performance.