Molecular and Cellular Radiation Biology Group, Department of Charged Particle Therapy Research, Institute for Quantum Medical Science, National Institutes for Quantum Science and Technology, 4-9-1 Anagawa, Chiba-shi, Chiba 263-8555, Japan.
Project "Quantum-Applied Biotechnology", Department of Quantum-Applied Biosciences, Takasaki Institute of Advanced Quantum Science, Foundational Quantum Technology Research Directorate, National Institutes for Quantum Science and Technology, 1233 Watanuki-machi, Takasaki-shi, Gunma 370-1292, Japan.
J Radiat Res. 2023 Sep 22;64(5):824-832. doi: 10.1093/jrr/rrad059.
We investigated the radiation-quality-dependent bystander cellular effects using heavy-ion microbeams with different ion species. The heavy-ion microbeams were produced in Takasaki Ion Accelerators for Advanced Radiation Application, National Institutes for Quantum Science and Technology. Carbon (12C5+, 220 MeV), neon (20Ne7+, 260 MeV) and argon (40Ar13+, 460 MeV) ions were used as the microbeams, collimating the beam size with a diameter of 20 μm. After 0.5 and 3 h of irradiation, the surviving fractions (SFs) are significantly lower in cells irradiated with carbon ions without a gap-junction inhibitor than those irradiated with the inhibitor. However, the same SFs with no cell killing were found with and without the inhibitor at 24 h. Conversely, no cell-killing effect was observed in argon-ion-irradiated cells at 0.5 and 3 h; however, significantly low SFs were found at 24 h with and without the inhibitor, and the effect was suppressed using vitamin C and not dimethyl sulfoxide. The mutation frequency (MF) in cells irradiated with carbon ions was 8- to 6-fold higher than that in the unirradiated control at 0.5 and 3 h; however, no mutation was observed in cells treated with the gap-junction inhibitor. At 24 h, the MFs induced by each ion source were 3- to 5-fold higher and the same with and without the inhibitor. These findings suggest that the bystander cellular effects depend on the biological endpoints, ion species and time after microbeam irradiations with different pathways.
我们使用具有不同离子种类的重离子微束研究了辐射品质依赖性旁观者细胞效应。重离子微束是在量子科学与技术国立研究所的高崎离子加速器中产生的。我们使用碳（12C5+，220 MeV）、氖（20Ne7+，260 MeV）和氩（40Ar13+，460 MeV）离子作为微束，并将光束直径缩小到 20 μm。在照射后 0.5 和 3 小时，未用缝隙连接抑制剂照射的细胞的存活分数（SF）明显低于用抑制剂照射的细胞。然而，在 24 小时时，无论是否有抑制剂，SF 相同，没有细胞杀伤。相反，在 0.5 和 3 小时时，氩离子照射的细胞没有观察到细胞杀伤效应；然而，无论是否有抑制剂，在 24 小时时都发现 SF 明显较低，并且使用维生素 C 而不是二甲基亚砜抑制了该效应。在 0.5 和 3 小时时，用碳离子照射的细胞的突变频率（MF）比未照射对照细胞高 8 到 6 倍；然而，用缝隙连接抑制剂处理的细胞没有观察到突变。在 24 小时时，每种离子源诱导的 MF 均高 3 到 5 倍，并且无论是否有抑制剂，结果均相同。这些发现表明，旁观者细胞效应取决于生物学终点、离子种类以及用不同途径照射微束后的时间。
