Artificial gravity partially protects space-induced neurological deficits in Drosophila melanogaster

Spaceflight poses risks to the central nervous system (CNS), and understanding neurological responses is important for future missions. We report CNS changes in Drosophila aboard the International Space Station in response to microgravity (SFμg) and artificially simulated Earth-gravity (SF1g) via inflight centrifugation as a countermeasure. While inflight behavioral analyses of SFμg exhibit increased activity, postflight analysis displays significant climbing defects, highlighting the sensitivity of behavior to altered gravity. Multi-omics analysis shows alterations in metabolic, oxidative stress, and synaptic transmission pathways in both SFμg and SF1g; however, neurological changes immediately postflight, including neuronal loss, glial cell count alterations, oxidative damage, and apoptosis, are seen only in SFμg. Additionally, progressive neuronal loss and a glial phenotype in SF1g and SFμg brains, with pronounced phenotypes in SFμg, are seen upon acclimation to Earth conditions. Overall, our results indicate that artificial gravity partially protects the CNS from the adverse effects of spaceflight.

航天飞行会对中枢神经系统（central nervous system，CNS）造成损伤，解析其神经响应机制对于未来航天任务至关重要。本研究报道了搭乘国际空间站（International Space Station）的果蝇（Drosophila）在微重力（microgravity，SFμg）环境下，以及通过在轨离心（inflight centrifugation）实施人工模拟地球重力（artificially simulated Earth-gravity，SF1g，作为对抗措施）时的中枢神经系统变化。尽管在轨行为分析显示微重力组（SFμg）果蝇的活动水平升高，但飞行后分析却发现其存在显著的攀爬能力缺陷，这凸显了行为模式对重力改变的敏感性。多组学（multi-omics）分析表明，微重力组（SFμg）与模拟重力组（SF1g）果蝇的代谢、氧化应激（oxidative stress）及突触传递（synaptic transmission）通路均出现异常；但飞行后即刻观测到的神经变化——包括神经元丢失（neuronal loss）、神经胶质细胞（glial cell）数量改变、氧化损伤与细胞凋亡（apoptosis）——仅见于微重力组（SFμg）。此外，在适应地球环境后，可观测到模拟重力组（SF1g）与微重力组（SFμg）果蝇大脑均出现进行性神经元丢失（progressive neuronal loss）及胶质细胞表型（glial phenotype）异常，其中微重力组（SFμg）的表型更为显著。综上，本研究结果表明人工重力可部分减轻航天飞行对中枢神经系统造成的不良影响。