Radiobiology Unit, Molecular and Cellular Biology expert group, Belgian Nuclear Research Centre, SCK•CEN, Mol, Belgium ; Laboratory of Biochemistry and Molecular Cytology, Department of Molecular Biotechnology, Ghent University, Ghent, Belgium.
PLoS One. 2013 Sep 16;8(9):e73857. doi: 10.1371/journal.pone.0073857. eCollection 2013.
One of the objectives of the current international space programmes is to investigate the possible effects of the space environment on the crew health. The aim of this work was to assess the particular effects of simulated microgravity on mature primary neuronal networks and specially their plasticity and connectivity. For this purpose, primary mouse neurons were first grown for 10 days as a dense network before being placed in the Random Positioning Machine (RPM), simulating microgravity. These cultures were then used to investigate the impact of short- (1 h), middle- (24 h) and long-term (10 days) exposure to microgravity at the level of neurite network density, cell morphology and motility as well as cytoskeleton properties in established two-dimensional mature neuronal networks. Image processing analysis of dense neuronal networks exposed to simulated microgravity and their subsequent recovery under ground conditions revealed different neuronal responses depending on the duration period of exposure. After short- and middle-term exposures to simulated microgravity, changes in neurite network, neuron morphology and viability were observed with significant alterations followed by fast recovery processes. Long exposure to simulated microgravity revealed a high adaptation of single neurons to the new gravity conditions as well as a partial adaptation of neuronal networks. This latter was concomitant to an increase of apoptosis. However, neurons and neuronal networks exposed for long-term to simulated microgravity required longer recovery time to re-adapt to the ground gravity. In conclusion, a clear modulation in neuronal plasticity was evidenced through morphological and physiological changes in primary neuronal cultures during and after simulated microgravity exposure. These changes were dependent on the duration of exposure to microgravity.
当前国际太空计划的目标之一是研究太空环境对机组人员健康的可能影响。本工作的目的是评估模拟微重力对成熟原代神经元网络的特殊影响，特别是其可塑性和连通性。为此，原代小鼠神经元首先在 RPM 中培养 10 天以形成致密网络，模拟微重力。然后，将这些培养物用于研究在二维成熟神经元网络中，在神经元网络密度、细胞形态和运动以及细胞骨架特性水平上，短期（1 h）、中期（24 h）和长期（10 天）暴露于微重力对神经突网络密度的影响。对暴露于模拟微重力的致密神经元网络及其随后在地面条件下恢复的图像处理分析显示，不同的神经元对暴露持续时间的反应不同。在模拟微重力的短期和中期暴露后，观察到神经突网络、神经元形态和活力的变化，随后出现显著改变和快速恢复过程。长期暴露于模拟微重力导致单个神经元对新重力条件的高度适应，以及神经元网络的部分适应。后者伴随着细胞凋亡的增加。然而，暴露于模拟微重力下的神经元和神经元网络需要更长的恢复时间才能重新适应地面重力。总之，在模拟微重力暴露期间和之后，原代神经元培养物的形态和生理变化证明了神经元可塑性的明显调节。这些变化取决于暴露于微重力的持续时间。
