Raber Jacob, Holden Sarah, Sudhakar Reetesh, Hall Reed, Glaeser Breanna, Lenarczyk Marek, Rockwell Kristen, Nawarawong Natalie, Sterrett Jennifer, Perez Ruby, Leonard Scott William, Morré Jeffrey, Choi Jaewoo, Kronenberg Amy, Borg Alexander, Kwok Andy, Stevens Jan Frederik, Olsen Christopher M, Willey Jeffrey S, Bobe Gerd, Baker John
Department of Behavioral Neuroscience, Oregon Health and Science University, Portland, OR, United States.
Department of Neurology, Psychiatry, and Radiation Medicine, Division of Neuroscience, ONPRC, Oregon Health and Science University, Portland, OR, United States.
Front Physiol. 2021 Sep 27;12:746509. doi: 10.3389/fphys.2021.746509. eCollection 2021.
A limitation of simulated space radiation studies is that radiation exposure is not the only environmental challenge astronauts face during missions. Therefore, we characterized behavioral and cognitive performance of male WAG/Rij rats 3 months after sham-irradiation or total body irradiation with a simplified 5-ion mixed beam exposure in the absence or presence of simulated weightlessness using hindlimb unloading (HU) alone. Six months following behavioral and cognitive testing or 9 months following sham-irradiation or total body irradiation, plasma and brain tissues (hippocampus and cortex) were processed to determine whether the behavioral and cognitive effects were associated with long-term alterations in metabolic pathways in plasma and brain. Sham HU, but not irradiated HU, rats were impaired in spatial habituation learning. Rats irradiated with 1.5 Gy showed increased depressive-like behaviors. This was seen in the absence but not presence of HU. Thus, HU has differential effects in sham-irradiated and irradiated animals and specific behavioral measures are associated with plasma levels of distinct metabolites 6 months later. The combined effects of HU and radiation on metabolic pathways in plasma and brain illustrate the complex interaction of environmental stressors and highlights the importance of assessing these interactions.
模拟太空辐射研究的一个局限性在于，辐射暴露并非宇航员在执行任务期间面临的唯一环境挑战。因此，我们对雄性WAG/Rij大鼠在假照射或全身照射后3个月的行为和认知表现进行了表征，照射采用简化的5离子混合束，在单独使用后肢卸载（HU）模拟失重或不模拟失重的情况下进行。在行为和认知测试6个月后，或在假照射或全身照射9个月后，对血浆和脑组织（海马体和皮质）进行处理，以确定行为和认知影响是否与血浆和大脑代谢途径的长期改变有关。假照射HU组大鼠（而非照射HU组大鼠）在空间习惯化学习方面受损。接受1.5 Gy照射的大鼠表现出更多的抑郁样行为。这一现象在未进行HU处理的大鼠中出现，而在进行HU处理的大鼠中未出现。因此，HU对假照射和照射动物具有不同的影响，特定的行为指标与6个月后血浆中不同代谢物的水平相关。HU和辐射对血浆和大脑代谢途径的综合影响说明了环境应激源之间复杂的相互作用，并突出了评估这些相互作用的重要性。
