|RABIN, BERNARD - University Of Maryland
|ROTTMAN, VICTORIA - University Of Maryland
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 12/18/2020
Publication Date: 2/1/2021
Citation: Rabin, B.M., Rottman, V., Shukitt Hale, B. 2021. Effects of preexposure to 4He particles on the alteration of cognitive performance produced by exposure to 56Fe particles in male and female rats. [abstract] NASA Human Research Program IWS 2021 (online), Program #1105-002.
Technical Abstract: Acute exposure to 56Fe particles can affect cognitive performance which has the potential to affect the performance of astronauts on exploratory class missions. These adverse cognitive deficits are similar to those seen in aging and are thought to be caused by similar mechanisms, i.e., oxidative stress and neuroinflammation. However, it is unlikely that astronauts will be exposed to a single acute dose of these particles of sufficient intensity to affect cognition. Most likely they will be exposed to low doses of different particles separated by intervals of varying length, which is similar to what occurs in aging. Because a significant component of the radiation dose within a spacecraft will be from 4He particles, the present experiment was designed to evaluate the effect of preexposure to 4He particles on the alteration of cognitive performance produced by exposure to 56Fe Particles. Male and female rats were given whole body exposures to a subthreshold dose of 4He particles (0.015 cGy, 300 MeV/n). Seventy-two hours later they were exposed to either a subthreshold (20 cGy) or suprathreshold (50 cGy) dose of 56Fe particles (600 MeV/n). Non-preexposed subjects were taken to the NSRL, placed in restraining tubes and walked around the facility, but not irradiated. The rats were then shipped to UMBC where they were tested on a novel object recognition task, novel spatial location task and operant responding on an ascending fixed-ratio schedule. The initial evaluation of cognitive performance was 1-4 months after irradiation. A second evaluation of performance was conducted 10-12 months after exposure. The results showed that the effects of preexposure to 4He particles on 56Fe particle-induced changes in cognitive performance varied as a function of three factors: cognitive task (more reliable effects were seen with operant responding (a measure of the motivation of an organism to work for food reinforcement); sex (preexposure to 4He particles enhanced the disruption of performance in male but not female subjects); and time after exposure (the pattern of responding of both the non-preexposed and preexposed subjects differed as a function of time since exposure). The present results are consistent with previous observations that female rats are less susceptible to the deleterious effects of exposure to HZE particles than are male rats. They also indicate that the effects of exposure to HZE particles on cognitive performance can be additive, even when separated by 72 hr. These changes in cognition are similar to those seen in aged animals, and antioxidant diets containing blueberries or strawberries have been shown to prevent these deficits.