The rapid growth of manned space flight results in more concerns about health risks and an urgent need for health assessment for space travel. The cosmic environment is complicated and full of radiation. Because of their strong biological effects, heavy ions such as 56Fe ions are considered to be an important component of these lethal galactic rays. Due to the importance of brain function to astronauts, we explored the long-term effects and potential mechanisms of 56Fe ion radiation on mice brains containing the hippocampus. In our study, radiation doses were carried out with 0.5 Gy, 1 Gy or 2 Gy. One month after whole-body 56Fe ion exposure, the Morris water maze test was performed to assess the ability of spatial learning and memory. A histological study was used for pathology analysis of the hippocampus. Alteration of oxidative stress was reflected by MDA and GSH and oxidative DNA damage marked by 8-OHdG was detected by biochemical and immunofluorescence methods. In our results, irradiated groups exhibited significant changes in behavioral performance and also showed loose and edematous arrangement in the pathological characteristics. Furthermore, whole brain levels of MDA, GSH and 8-OHdG increased in the irradiated groups. In addition, increased expression of 8-OHdG can also be detected by immunofluorescence in the hippocampus. Our findings revealed a linkage between radiation-induced oxidative stress and behavioral deficits. This may suggest an underlying mechanism of brain tissue protection and risk assessment in manned space flight.

中文翻译：

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56Fe辐射通过小鼠的氧化应激引起认知障碍。

载人航天飞行的迅速增长导致人们更加担心健康风险，并迫切需要对太空旅行进行健康评估。宇宙环境十分复杂，充满了辐射。由于其强大的生物学效应，重离子（如56Fe离子）被认为是这些致命银河射线的重要组成部分。由于大脑功能对宇航员的重要性，我们探讨了56Fe离子辐射对含有海马体的小鼠大脑的长期影响和潜在机制。在我们的研究中，辐射剂量为0.5 Gy，1 Gy或2 Gy。全身56Fe离子暴露一个月后，进行了莫里斯水迷宫测试，以评估空间学习和记忆的能力。组织学研究用于海马的病理分析。MDA和GSH反映了氧化应激的变化，生化和免疫荧光方法检测到了以8-OHdG标记的氧化DNA损伤。在我们的结果中，受辐照组表现出明显的行为表现变化，并且在病理特征上也显示出疏松而水肿的排列。此外，辐照组的全脑MDA，GSH和8-OHdG水平升高。另外，还可以通过海马中的免疫荧光检测到8-OHdG的表达增加。我们的发现揭示了辐射诱导的氧化应激与行为缺陷之间的联系。这可能暗示了载人航天中脑组织保护和风险评估的潜在机制。