Abstract：
UNASSIGNED: Earlier evidence suggests that extremely low frequency magnetic fields (ELF MFs) can modify the effects of carcinogenic agents. However, the studies conducted so far with ionizing radiation as the co-exposure agent are sparse and have provided inconclusive results. We investigated whether 50 Hz MFs alone, or in combination with ionizing radiation alter cell biological variables relevant to cancer and the biological effects of ionizing radiation.
UNASSIGNED: Human SH-SY5Y neuroblastoma cells were sham exposed or exposed to 100 or 500 µT MF for 24 h either before or after ionizing radiation exposure (0, 0.4 or 2 Gy). After the exposures, cells were assayed for viability, clonogenicity, reactive oxygen species, caspase-3 activity, and cell cycle distribution. Cell cycle distribution was assayed with propidium iodide staining followed by flow cytometry analysis and ROS levels were assayed together with cell viability by double staining with DeepRed and Sytox Blue followed by flow cytometry analysis.
UNASSIGNED: Increased caspase-3 activity was observed in cells exposed to 500 µT MF before or after ionizing radiation. Furthermore, exposure to the 500 µT MF after the ionizing radiation decreased the percentage of cells in S-phase. No changes in the ROS levels, clonogenicity, or viability of the cells were observed in the MF exposed groups compared to the corresponding sham exposed groups, and no MF effects were observed in cells exposed at 100 µT.
UNASSIGNED: Only the 500 µT magnetic flux density affected SH-SY5Y cells significantly. The effects were small but may nevertheless help to understand how MFs modify the effects of ionizing radiation. The increase in caspase-3 activity may not reflect effects on apoptosis, as no changes were observed in the subG1 phase of the cell cycle. In contrast to some earlier findings, 50 Hz MF exposure after ionizing radiation was not less effective than MF treatment given prior to ionizing radiation.
UNASSIGNED: Human SH-SY5Y neuroblastoma cells were sham exposed or exposed to 100 or 500 µT MF for 24 h either before or after ionizing radiation exposure (0, 0.4 or 2 Gy). After the exposures, cells were assayed for viability, clonogenicity, reactive oxygen species, caspase-3 activity, and cell cycle distribution. Cell cycle distribution was assayed with propidium iodide staining followed by flow cytometry analysis and ROS levels were assayed together with cell viability by double staining with DeepRed and Sytox Blue followed by flow cytometry analysis.
UNASSIGNED: Increased caspase-3 activity was observed in cells exposed to 500 µT MF before or after ionizing radiation. Furthermore, exposure to the 500 µT MF after the ionizing radiation decreased the percentage of cells in S-phase. No changes in the ROS levels, clonogenicity, or viability of the cells were observed in the MF exposed groups compared to the corresponding sham exposed groups, and no MF effects were observed in cells exposed at 100 µT.
UNASSIGNED: Only the 500 µT magnetic flux density affected SH-SY5Y cells significantly. The effects were small but may nevertheless help to understand how MFs modify the effects of ionizing radiation. The increase in caspase-3 activity may not reflect effects on apoptosis, as no changes were observed in the subG1 phase of the cell cycle. In contrast to some earlier findings, 50 Hz MF exposure after ionizing radiation was not less effective than MF treatment given prior to ionizing radiation.
摘要：
■早期的证据表明，极低频磁场（ELFMFs）可以改变致癌剂的作用。然而,到目前为止，使用电离辐射作为共同暴露剂进行的研究很少，并且提供了不确定的结果。我们调查了50HzMF是否单独，或与电离辐射结合改变与癌症相关的细胞生物学变量和电离辐射的生物学效应。
■在电离辐射暴露（0、0.4或2Gy）之前或之后，将人SH-SY5Y神经母细胞瘤细胞假暴露或暴露于100或500µTMF24小时。曝光后，测定细胞的活力，克隆性,活性氧，caspase-3活性，和细胞周期分布。用碘化丙啶染色然后流式细胞术分析来测定细胞周期分布,并且通过用DeepRed和SytoxBlue双重染色然后流式细胞术分析来测定ROS水平以及细胞活力。
■在电离辐射之前或之后暴露于500µTMF的细胞中观察到caspase-3活性增加。此外，电离辐射后暴露于500µTMF会降低S期细胞的百分比。ROS水平没有变化，克隆性,与相应的假暴露组相比，在MF暴露组中观察到细胞的活力，在暴露于100µT的细胞中没有观察到MF效应。
■只有500µT的磁通密度对SH-SY5Y细胞有显著影响。影响很小，但可能有助于了解MF如何改变电离辐射的影响。caspase-3活性的增加可能不能反映对细胞凋亡的影响。因为在细胞周期的亚G1期未观察到变化。与之前的一些发现相反，电离辐射后的50HzMF暴露并不比电离辐射前的MF治疗有效。
■在电离辐射暴露（0、0.4或2Gy）之前或之后，将人SH-SY5Y神经母细胞瘤细胞假暴露或暴露于100或500µTMF24小时。曝光后，测定细胞的活力，克隆性,活性氧，caspase-3活性，和细胞周期分布。用碘化丙啶染色然后流式细胞术分析来测定细胞周期分布,并且通过用DeepRed和SytoxBlue双重染色然后流式细胞术分析来测定ROS水平以及细胞活力。
■在电离辐射之前或之后暴露于500µTMF的细胞中观察到caspase-3活性增加。此外，电离辐射后暴露于500µTMF会降低S期细胞的百分比。ROS水平没有变化，克隆性,与相应的假暴露组相比，在MF暴露组中观察到细胞的活力，在暴露于100µT的细胞中没有观察到MF效应。
■只有500µT的磁通密度对SH-SY5Y细胞有显著影响。影响很小，但可能有助于了解MF如何改变电离辐射的影响。caspase-3活性的增加可能不能反映对细胞凋亡的影响。因为在细胞周期的亚G1期未观察到变化。与之前的一些发现相反，电离辐射后的50HzMF暴露并不比电离辐射前的MF治疗有效。
