宇宙辐射剂量或可改变宇航员大脑和行为（视频） | BMC Genomics 论文推荐 | 自由微信

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宇宙辐射剂量或可改变宇航员大脑和行为（视频） | BMC Genomics 论文推荐

2016-12-09 科研圈

本文转载自公众号 BioMedCentral BBBbiomedi BIBIoBIO （ID：BMC2000）

一项新的研究为将来计划飞往火星的宇航员们带来了坏消息：在深空任务中遭受的宇宙辐射剂量足以改变大脑和行为。其作用是暂时性的，而且到目前为止仅在小鼠身上被观察到；然而研究人员已经开始了解在通常关注的癌症之外，辐射如何造成其它健康危害。

来源 BMC 中国

本文发表在 BioMed Central 旗下系列期刊 BMC Genomics上，原文标题：

56Fe照射对认知以及海马体DNA甲基化和基因表达的短期和长期影响

背景：

宇航员在深太空中执行长期的空间任务时会暴露于⁵⁶Fe离子下，这可能会造成重大的健康危害的。我们先前的研究表明，在用⁵⁶Fe离子照射的2个月龄的小鼠中，海马体（一种认知功能的关键结构）参与的物体辨认功能会受到影响。本文中，我们研究了用⁵⁶Fe离子照射的6个月龄小鼠的物体辨认；此类小鼠的生物学年龄与宇航员的典型年龄更加相关。此外，由于介导⁵⁶Fe离子对海马体功能的有害作用的机理尚不清楚，因此我们检测了伴随基因表达变化而变化的海马体网络，这些变化包括了突触可塑性和记忆、基因表达、以及胞嘧啶甲基化（5mC）和羟甲基化（5hmC）的表观遗传等多种变化。我们评估了在早期（2周）和晚期（20周）时间点，全身⁵⁶Fe离子照射对依赖于海马体的记忆能力和海马体网络稳定性的影响，以及这些影响是否与海马体DNA甲基化（5mC和5hmC）和基因表达的表观遗传变化相关。

结果：

在2周时间点，物体辨认和网络稳定性在0.1和0.4 Gy剂量照射后受损，但在0.2Gy剂量照射后不受影响。在20周时间点，在所使用的任何照射剂量下，没有观察到物体辨认或网络稳定性的损伤。与这种模式一致，与2周时间点相比，在20周时间点5hmC基因类别的途径的显著性较低，尽管还未被消除。类似地，在2周时间点观察到5mC基因途径有显著的变化，但在20周时间点没有观察到明显的基因类别。仅5hmC的变化与基因表达的变化相关。

结论：

暴露于⁵⁶Fe离子后在海马体中的剂量和时间依赖性的表观基因组重塑是与行为变化相关的。

本文归 BioMed Central 所有，中文内容仅供参考，一切内容以英文原版为主。

相关论文信息

题目 Short- and long-term effects of 56Fe irradiation on cognition and hippocampal DNA methylation and gene expression

作者 Soren Impey Timothy Jopson, Carl Pelz, Amanuel Tafessu, Fatema Fareh, Damian Zuloaga, Tessa Marzulla, Lara-Kirstie Riparip, Blair Stewart, Susanna Rosi, Mitchell S. Turker and Jacob RaberEmail authorView ORCID ID profile

刊期 BMC Genomics 201617:825

DOI: 10.1186/s12864-016-3110-7© The Author(s). 2016

发表日期 Published: 24 October 2016

摘 46 32449 46 14986 0 0 2309 0 0:00:14 0:00:06 0:00:08 2928 46 32449 46 14986 0 0 2014 0 0:00:16 0:00:07 0:00:09 3069

Background

Astronauts are exposed to 56Fe ions that may pose a significant health hazard during and following prolonged missions in deep space. We showed previously that object recognition requiring the hippocampus, a structure critical for cognitive function, is affected in 2-month-old mice irradiated with 56Fe ions. Here we examined object recognition in 6-month-old mice irradiated with 56Fe ions, a biological age more relevant to the typical ages of astronauts. Moreover, because the mechanisms mediating the detrimental effects of 56Fe ions on hippocampal function are unclear, we examined changes in hippocampal networks involved in synaptic plasticity and memory, gene expression, and epigenetic changes in cytosine methylation (5mC) and hydroxymethylation (5hmC) that could accompany changes in gene expression. We assessed the effects of whole body 56Fe ion irradiation at early (2 weeks) and late (20 weeks) time points on hippocampus-dependent memory and hippocampal network stability, and whether these effects are associated with epigenetic changes in hippocampal DNA methylation (both 5mC and 5hmC) and gene expression.

Results

At the two-week time point, object recognition and network stability were impaired following irradiation at the 0.1 and 0.4 Gy dose, but not following irradiation at the 0.2 Gy dose. No impairments in object recognition or network stability were seen at the 20-week time point at any irradiation dose used. Consistent with this pattern, the significance of pathways for gene categories for 5hmC was lower, though not eliminated, at the 20-week time point compared to the 2-week time point. Similarly, significant changes were observed for 5mC gene pathways at the 2-week time point, but no significant gene categories were observed at the 20-week time point. Only the 5hmC changes tracked with gene expression changes.

Conclusions

Dose- and time-dependent epigenomic remodeling in the hippocampus following 56Fe ion exposure correlates with behavioral changes.

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