Effects of 50-Hz magnetic field exposure on superoxide radical anion formation and HSP70 induction in human K562 cells
Effects of 50-Hz magnetic field exposure on superoxide radical anion formation and HSP70 induction in human K562 cells
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DOI：
10.1007/s00411-010-0306-0
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发表时间：
2010-11-01
影响因子：
1.7
通讯作者：
Mattsson, Mats-Olof
中科院分区：
文献类型：
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作者：
Mannerling, Ann-Christine;Simko, Myrtill;Mattsson, Mats-Olof
流行病学研究表明，暴露在低水平极低频率(ELF)磁场(MF)与某些癌症和神经退行性疾病之间存在相关性。实验研究没有提供这种效应的任何机制，尽管在显著高于流行病学研究中遇到的通量密度水平时，自由基稳态和应激反应蛋白水平可能会受到影响。在这里，我们报道了磁场暴露(50赫兹正弦波，1h，0.025-0.10mT，垂直或水平方向)对人白血病细胞株K562不同细胞参数(增殖、细胞周期分布、超氧阴离子和热休克蛋白70蛋白水平)的影响。阳性对照热处理(42a℃，1h)对细胞增殖和超氧阴离子产生没有影响，但导致细胞在G2期积累，并增加了应激蛋白HSP70。磁场暴露(0.10mT，1h)对细胞周期动力学和细胞增殖均无影响。与假手术对照组和热处理相比，垂直和水平磁场暴露1小时后，在不同的磁通密度下，HSP70水平都显著且短暂地增加了两倍。这种暴露还增加了(30-40%)超氧阴离子水平，与阳性对照PMA相当。加入自由基清除剂(褪黑素或1，10-菲托林)可抑制MF诱导的HSP70的增加。总之，K562细胞对ELF MF的早期反应似乎是氧自由基的增加，导致HSP70的诱导。此外，结果还表明，在0.025 mT或更低的频率下，50赫兹的磁场对K562细胞的作用存在一个电流密度阈值，而且激活参数是磁场，而不是感应电场。
Epidemiological studies suggest a correlation between exposure to low-level extremely low-frequency (ELF) magnetic fields (MF) and certain cancers and neurodegenerative diseases. Experimental studies have not provided any mechanism for such effects, although at flux density levels significantly higher than the ones encountered in epidemiological studies, radical homoeostasis and levels of stress response proteins can be affected. Here, we report on the influence of MF exposure (50-Hz sine wave; 1 h; 0.025-0.10 mT; vertical or horizontal MF exposure direction) on different cellular parameters (proliferation, cell cycle distribution, superoxide radical anion, and HSP70 protein levels) in the human leukaemia cell line K562. The positive control heat treatment (42A degrees C, 1 h) did not affect either cell proliferation or superoxide radical anion production but caused accumulation of cells in the G2 phase and increased the stress protein HSP70. MF exposure (0.10 mT, 1 h) did not affect either cell cycle kinetics or proliferation. Both vertical and horizontal MF exposures for 1 h caused significantly and transiently increased HSP70 levels (> twofold), at several flux densities, compared to sham controls and also compared to heat treatment. This exposure also increased (30-40%) the levels of the superoxide radical anion, comparable to the positive control PMA. Addition of free radical scavengers (melatonin or 1,10-phenantroline) inhibited the MF-induced increase in HSP70. In conclusion, an early response to ELF MF in K562 cells seems to be an increased amount of oxygen radicals, leading to HSP70 induction. Furthermore, the results suggest that there is a flux density threshold where 50-Hz MF exerts its effects on K562 cells, at or below 0.025 mT, and also that it is the MF, and not the induced electric field, which is the active parameter.