Laboratory of Neurochemistry, Graduate School of Human and Environmental Studies, Kyoto University, Sakyo-ku, Kyoto, 606-8501, Japan.
Neurochem Res. 2012 Feb;37(2):387-93. doi: 10.1007/s11064-011-0623-y. Epub 2011 Oct 21.
The effect of heavy ion radiation exposure of the spinal cord on the properties of the motoneurons innervating the slow soleus and fast plantaris muscles was investigated. A 15-, 20-, 40-, 50-, or 70-Gy dose of carbon ions (5 Gy/min) was applied to the 2nd to the 6th lumbar segments of the spinal cord in rats. After a 1-month recovery period, the number and cell body size of the irradiated motoneurons innervating the soleus and plantaris muscles did not differ from that of the non-irradiated controls, irrespective of the dose received. However, the oxidative enzyme activity of these motoneurons was decreased by heavy ion radiation at doses of 40, 50, and 70 Gy compared to that of the non-irradiated controls. This decrease in oxidative enzyme activity levels in the motoneurons returned to that of the non-irradiated controls after a 6-month recovery period. We conclude that heavy ion radiation at doses of 40-70 Gy reversibly decreases the oxidative enzyme activity of motoneurons in the spinal cord of rats.
研究了脊髓重离子辐射暴露对支配慢缩肌和快缩肌运动神经元特性的影响。采用 15、20、40、50 或 70 Gy 的碳离子（5 Gy/min）剂量照射大鼠第 2 至第 6 腰椎节段。经过 1 个月的恢复期，无论接受的剂量如何，照射的支配比目鱼肌和跖肌的运动神经元的数量和细胞体大小与未照射的对照组没有差异。然而，与未照射的对照组相比，40、50 和 70 Gy 的重离子辐射会降低这些运动神经元的氧化酶活性。经过 6 个月的恢复期，运动神经元中氧化酶活性水平的这种降低恢复到未照射的对照组水平。我们的结论是，40-70 Gy 的重离子辐射可使大鼠脊髓中的运动神经元的氧化酶活性可逆性降低。
