Rola Radoslaw, Sarkissian Vahe, Obenaus Andre, Nelson Gregory A, Otsuka Shinji, Limoli Charles L, Fike John R
Department of Neurological Surgery, University of California, San Francisco, San Francisco, California 94143, USA.
Radiat Res. 2005 Oct;164(4 Pt 2):556-60. doi: 10.1667/rr3412.1.
Exposure to heavy-ion radiation is considered a potential health risk in long-term space travel. It may result in the loss of critical cellular components in complex systems like the central nervous system (CNS), which could lead to performance decrements that ultimately could compromise mission goals and long-term quality of life. Specific hippocampal-dependent cognitive impairment occurs after whole-body 56Fe-particle irradiation, and while the pathogenesis of this effect is not yet clear, it may involve damage to neural precursor cells in the hippocampal dentate gyrus. We irradiated mice with 1-3 Gy of 12C or 56Fe ions and 9 months later quantified proliferating cells and immature neurons in the dentate subgranular zone (SGZ). Our results showed that reductions in these cells were dependent on the dose and LET. When compared with data for mice that were studied 3 months after 56Fe-particle irradiation, our current data suggest that these changes are not only persistent but may worsen with time. Loss of precursor cells was also associated with altered neurogenesis and a robust inflammatory response. These results indicate that high-LET radiation has a significant and long-lasting effect on the neurogenic population in the hippocampus that involves cell loss and changes in the microenvironment.
在长期太空旅行中，暴露于重离子辐射被认为是一种潜在的健康风险。它可能导致中枢神经系统（CNS）等复杂系统中关键细胞成分的丧失，这可能导致性能下降，最终可能危及任务目标和长期生活质量。全身56Fe粒子照射后会出现特定的海马依赖性认知障碍，虽然这种效应的发病机制尚不清楚，但可能涉及海马齿状回神经前体细胞的损伤。我们用1 - 3 Gy的12C或56Fe离子照射小鼠，9个月后对齿状颗粒下区（SGZ）的增殖细胞和未成熟神经元进行定量分析。我们的结果表明，这些细胞的减少取决于剂量和传能线密度（LET）。与56Fe粒子照射3个月后研究的小鼠数据相比，我们目前的数据表明这些变化不仅持续存在，而且可能随时间恶化。前体细胞的丧失还与神经发生改变和强烈的炎症反应有关。这些结果表明，高LET辐射对海马中的神经源性群体有显著且持久的影响，涉及细胞丢失和微环境变化。
