Laboratory of Cell Biology and Life Science, Graduate School of Human and Environmental Studies, Kyoto University, Sakyo-ku, Kyoto, 606-8501, Japan,
Neurochem Res. 2013 Oct;38(10):2160-7. doi: 10.1007/s11064-013-1124-y. Epub 2013 Aug 14.
Cell body size and succinate dehydrogenase activity of motoneurons in the dorsolateral region of the ventral horn in the lumbar and cervical segments of the mouse spinal cord were assessed after long-term exposure to microgravity and compared with those of ground-based controls. Mice were housed in a mouse drawer system on the International Space Station for 13 weeks. The mice were transported to the International Space Station by the Space Shuttle Discovery and returned to Earth by the Space Shuttle Atlantis. No changes in the cell body size of motoneurons were observed in either segment after exposure to microgravity, but succinate dehydrogenase activity of small-sized (<300 μm(2)) gamma and medium-sized (300-700 μm(2)) alpha motoneurons, which have higher succinate dehydrogenase activity than large-sized (>700 μm(2)) alpha motoneurons, in both segments was lower than that of ground-based controls. We concluded that exposure to microgravity for longer than 3 months induced decreased succinate dehydrogenase activity of both gamma and slow-type alpha motoneurons. In particular, the decreased succinate dehydrogenase activity of gamma motoneurons was observed only after long-term exposure to microgravity.
在长期暴露于微重力环境后，评估了小鼠脊髓腰段和颈段腹角背外侧区运动神经元的胞体大小和琥珀酸脱氢酶活性，并与地面对照组进行了比较。将小鼠置于国际空间站的小鼠抽屉系统中 13 周。使用发现号航天飞机将小鼠运送到国际空间站，并使用亚特兰蒂斯号航天飞机将其送回地球。在暴露于微重力后，两个节段中的运动神经元胞体大小均未发生变化，但琥珀酸脱氢酶活性较低小（<300μm(2)）γ和中型（300-700μm(2)）α运动神经元，它们的琥珀酸脱氢酶活性高于大型（>700μm(2)）α运动神经元，两个节段的活性均低于地面对照组。我们得出结论，暴露于微重力 3 个月以上会导致γ和慢型α运动神经元的琥珀酸脱氢酶活性降低。特别是，只有在长期暴露于微重力后才观察到γ运动神经元琥珀酸脱氢酶活性降低。
