Tan Shaobo, Pei Weiwei, Huang Hao, Zhou Guangming, Hu Wentao
State Key Laboratory of Radiation Medicine and Protection, School of Radiation Medicine and Protection, Collaborative Innovation Center of Radiological Medicine of Jiangsu Higher Education Institutions, Soochow University, Suzhou, 215123, China.
NPJ Microgravity. 2020 Nov 5;6(1):34. doi: 10.1038/s41526-020-00123-7.
Radiation and microgravity are undoubtedly two major factors in space environment that pose a health threat to astronauts. However, the mechanistic study of their interactive biological effects is lacking. In this study, human lung bronchial epithelial Beas-2B cells were used to study the regulation of radiobiological effects by simulated microgravity (using a three-dimensional clinostat). It was found that simulated microgravity together with radiation induced drop of survival fraction, proliferation inhibition, apoptosis, and DNA double-strand break formation of Beas-2B cells additively. They also additively induced Ras-related C3 botulinum toxin substrate 2 (RAC2) upregulation, leading to increased NADPH oxidase activity and increased intracellular reactive oxygen species (ROS) yield. The findings indicated that simulated microgravity and ionizing radiation presented an additive effect on cell death of human bronchial epithelial cells, which was mediated by RAC2 to some extent. The study provides a new perspective for the better understanding of the compound biological effects of the space environmental factors.
辐射和微重力无疑是空间环境中对宇航员健康构成威胁的两个主要因素。然而，关于它们相互作用的生物学效应的机制研究却很缺乏。在本研究中，使用人肺支气管上皮Beas-2B细胞来研究模拟微重力（使用三维回转器）对放射生物学效应的调节作用。研究发现，模拟微重力与辐射共同作用可使Beas-2B细胞的存活分数下降、增殖受到抑制、发生凋亡并形成DNA双链断裂，这些效应具有相加作用。它们还能相加性地诱导Ras相关的C3肉毒杆菌毒素底物2（RAC2）上调，导致NADPH氧化酶活性增加以及细胞内活性氧（ROS）产量增加。研究结果表明，模拟微重力和电离辐射对人支气管上皮细胞死亡具有相加作用，且这种作用在一定程度上由RAC2介导。该研究为更好地理解空间环境因素的复合生物学效应提供了新的视角。
