Radiation Effect Mechanisms Research Group, Research Center for Radiation Protection, National Institute of Radiological Sciences, Chiba.
J Radiat Res. 2011;52(3):278-86. doi: 10.1269/jrr.10140. Epub 2011 Feb 19.
Effects of prenatal low-dose irradiations of heavy ions on the postnatal development of mice and of melanocytes have not been well studied. Pregnant females of C57BL/10J mice were irradiated whole-body at 9 days of gestation with a single acute dose of γ-rays, silicon (Si, 57 keV/µm), argon (Ar, 100 keV/µm) and iron (Fe, 220 keV/µm) ions. The effects were studied by scoring changes in the postnatal development of mice as well as in the pigmentation of cutaneous coats and tail-tips of their offspring 22 days after birth. The survival to day 22 decreased from the offspring exposed to 0.4 Gy of argon and iron ions and to 0.75 Gy of silicon ions. White spots were found in the mid-ventrum and tail-tips of irradiated offspring. The frequency and size of the white spots in the mid-ventrum in mice exposed to silicon, argon and iron ions were greater than those of γ-rays. Even in the low dose (0.1 Gy), γ-rays and heavy ions increased the frequency of the ventral spots. The RBE estimated by the frequency of the ventral spots was 2.3 (Si), 3.1 (Ar) and 4.5 (Fe). These results suggest that prenatal exposure to heavy ions possesses a greater effect on the postnatal development of mice as well as melanocyte development than does exposure to γ-rays.
产前低剂量重离子辐照对小鼠和黑素细胞的产后发育影响尚未得到很好的研究。C57BL/10J 小鼠的孕鼠在妊娠第 9 天全身接受单次急性γ射线、硅（Si，57keV/μm）、氩（Ar，100keV/μm）和铁（Fe，220keV/μm）离子照射。通过对出生后 22 天的后代的发育变化以及其皮肤和尾巴尖端的色素沉着进行评分来研究这些影响。暴露于 0.4Gy 氩和铁离子以及 0.75Gy 硅离子的后代的存活率降低。在照射后代的中腹部和尾巴尖端发现了白点。暴露于硅、氩和铁离子的小鼠中腹部白点的频率和大小大于γ射线。即使在低剂量（0.1Gy）下，γ射线和重离子也增加了腹部斑点的频率。通过腹部斑点的频率估计的 RBE 为 2.3（Si）、3.1（Ar）和 4.5（Fe）。这些结果表明，产前暴露于重离子对小鼠和黑素细胞的产后发育的影响大于暴露于γ射线。
