Laboratory of Radiation Biology, Joint Institute for Nuclear Research, 6 Joliot-Curie St., 141980 Dubna, Moscow Region, Russia; Biophysics Department, "Dubna" University, 19 Universitetskaya St., 141980 Dubna, Moscow Region, Russia.
Laboratory of Radiation Biology, Joint Institute for Nuclear Research, 6 Joliot-Curie St., 141980 Dubna, Moscow Region, Russia; Academy of Sciences of Moldova, Chișinău, Moldova.
Phys Med. 2016 Sep;32(9):1088-94. doi: 10.1016/j.ejmp.2016.08.006. Epub 2016 Aug 17.
Planning of the deep-space exploration missions raises a number of questions on the radiation protection of astronauts. One of the medical concerns is associated with exposure of a crew to highly energetic particles of galactic cosmic rays. Among many other health disorders, irradiation with these particles has a substantial impact on the central nervous system (CNS). Although radiation damage to CNS has been addressed extensively during the last years, the mechanisms underlying observed impairments remain mostly unknown. The present study reveals neurochemical and behavioural alterations induced in rats by 1Gy of 500MeV/u (12)C particles with a relatively moderate linear energy transfer (10.6keV/μm). It is found that exposure to carbon ions leads to significant modification of the normal monoamine metabolism dynamics as well as the locomotor, exploratory, and anxiety-like behaviours during a two-month period. The obtained results indicate an abnormal redistribution of monoamines and their metabolites in different brain regions after exposure. The most pronounced impairments are detected in the prefrontal cortex, nucleus accumbens, and hypothalamus that illustrate the sensitivity of these brain regions to densely ionizing radiations. It is also shown that exposure to (12)C particles enhances the anxiety in animals and accelerates the age-related reduction in their exploratory capability. The observed monoamine metabolism pattern may indicate the presence of certain compensatory mechanisms being induced in response to irradiation and capable of partial restoration of monoaminergic systems' functions. Overall, these findings support a possibility of CNS damage by space-born particles of a relatively moderate linear energy transfer.
深空探索任务的规划引发了许多关于宇航员辐射防护的问题。其中一个医学关注点与机组人员暴露于银河宇宙射线的高能粒子有关。除了许多其他健康障碍外，这些粒子的辐照对中枢神经系统（CNS）有实质性影响。尽管近年来广泛研究了 CNS 的辐射损伤，但观察到的损伤机制仍知之甚少。本研究揭示了 1Gy500MeV/u（12）C 粒子以相对适中的线性能量转移（10.6keV/μm）对大鼠的神经化学和行为改变。研究发现，暴露于碳离子会导致正常单胺代谢动力学以及运动、探索和焦虑样行为在两个月期间发生显著改变。研究结果表明，暴露后单胺及其代谢物在不同脑区的异常再分布。在额叶皮质、伏隔核和下丘脑观察到最明显的损伤，这些脑区对高电离辐射敏感。研究还表明，暴露于（12）C 粒子会增强动物的焦虑感，并加速其探索能力随年龄的下降。观察到的单胺代谢模式可能表明存在某些补偿机制，这些机制是为了应对辐照而被诱导的，能够部分恢复单胺能系统的功能。总的来说，这些发现支持了由相对适中线性能量转移的太空传播粒子引起的 CNS 损伤的可能性。
