Department of Radiobiology and Hygiene Management, Institute of Industrial Ecological Sciences, University of Occupational and Environmental Health, Iseigaoka Yahatanishi-ku, Kitakyushu, Fukuoka 807-8555, Japan.
Health and Medical Research Institute, Department of Life Science and Biotechnology, National Institute of Advanced Industrial Science and Technology (AIST), Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan.
J Radiat Res. 2021 Sep 13;62(5):804-811. doi: 10.1093/jrr/rrab026.
Radiation exposure has multiple effects on the brain, behavior and cognitive functions. It has been reported that high-dose (>20 Gy) radiation-induced behavior and cognitive aberration partly associated with severe tissue destruction. Low-dose (<3 Gy) exposure can occur in radiological disasters and cerebral endovascular treatment. However, only a few reports analyzed behavior and cognitive functions after low-dose irradiation. This study was undertaken to assess the relationship between brain neurochemistry and behavioral disruption in irradiated mice. The irradiated mice (0.5 Gy, 1 Gy and 3 Gy) were tested for alteration in their normal behavior over 10 days. A serotonin (5-HT), Dopamine, gamma-Aminobutyric acid (GABA) and cortisol analysis was carried out in blood, hippocampus, amygdala and whole brain tissue. There was a significant decline in the exploratory activity of mice exposed to 3 Gy and 1 Gy radiation in an open field test. We observed a significant short-term memory loss in 3 Gy and 1 Gy irradiated mice in Y-Maze. Mice exposed to 1 Gy and 3 Gy radiation exhibited increased anxiety in an elevated plus maze (EPM). The increased anxiety and memory loss patterns were also seen in 0.5 Gy irradiated mice, but the results were not statistically significant. In this study we observed that neurotransmitters are significantly altered after irradiation, but the neuronal cells in the hippocampus were not significantly affected. This study suggests that the low-dose radiation-induced cognitive impairment may be associated with the neurochemical in low-dose irradiation and unlike the high-dose scenario might not be directly related to the morphological changes in the brain.
辐射对大脑、行为和认知功能有多种影响。据报道，高剂量（>20Gy）辐射引起的行为和认知障碍部分与严重的组织破坏有关。低剂量（<3Gy）辐射可发生在放射灾害和脑血管内治疗中。然而，只有少数报道分析了低剂量照射后的行为和认知功能。本研究旨在评估照射后小鼠脑神经化学与行为障碍之间的关系。对 0.5Gy、1Gy 和 3Gy 照射的小鼠进行了 10 天的正常行为改变测试。对血液、海马体、杏仁核和全脑组织中的 5-羟色胺（5-HT）、多巴胺、γ-氨基丁酸（GABA）和皮质醇进行了分析。在旷场试验中，暴露于 3Gy 和 1Gy 辐射的小鼠的探索活动明显下降。在 Y 迷宫中，我们观察到 3Gy 和 1Gy 照射的小鼠短期记忆明显丧失。1Gy 和 3Gy 照射的小鼠在高架十字迷宫（EPM）中表现出焦虑增加。在 0.5Gy 照射的小鼠中也观察到了焦虑和记忆丧失的模式，但结果没有统计学意义。在这项研究中，我们观察到照射后神经递质显著改变，但海马体中的神经元细胞没有受到显著影响。本研究表明，低剂量辐射引起的认知障碍可能与低剂量照射的神经化学有关，与高剂量情况不同，可能与大脑形态变化没有直接关系。
