McFarlane E H, Dawe G S, Marks M, Campbell I C
Department of Neuroscience, Institute of Psychiatry, King's College London, UK.
Bioelectrochemistry. 2000 Sep;52(1):23-8. doi: 10.1016/s0302-4598(00)00078-7.
The effects of low electromagnetic field (EMF) exposure (4.5-15.8 microT, 50 Hz AC) on neurite outgrowth and cell division in rat PC12 pheochromocytoma cells were examined. The study involved two separate experimental series in which culture conditions during exposure to the magnetic fields differed. In series 1 (14 experiments in which culture conditions were not strongly conducive to cell differentiation [15% serum]), exposure to 4.5-8.25 microT for 23 h significantly inhibited neurite outgrowth by 21.5 +/- 1.3% (by Manova, p = 0.003). In contrast, in series 2 (12 experiments in which culture conditions promoted cellular differentiation [4% serum]), exposure to 4.35-8.25 microT for 23 h significantly stimulated neurite outgrowth by 16.9 +/- 1.1% (by Manova, p = 0.009). Thus, in both series, exposure to a narrow range of low EMF has significant, but opposite effects on neurite outgrowth. Exposure to higher fields, 8.25-12.5 microT (series 1) and 8.25-15.8 microT (series 2) had no significant effect on neurite outgrowth. These data, when considered with other reports, suggest that neuronal differentiation can be altered by low level EMF exposure. While this may not be detrimental, it merits further research. At present, the reasons for the significant changes in neurite outgrowth being confined to the same narrow field strength are unclear. As stated above, culture conditions in series 2 were more conducive to cell differentiation than those in series 1. This is reflected in the lower number of cells in control samples in series 2, at the end of the 23-h incubation, than in series 1 (- 16.9 +/- 1.7%, p = 0.003). As the same numbers were plated in both series, the medium used in series 1 allows more of the PC12 cells to divide; this is consistent with some cells reverting to a non-neuronal adrenal chromaffin phenotype [L. Greene, A. Tischler. Establishment of a noradrenergic clonal line of rat adrenal pheochromocytoma cells which respond to nerve growth factor. Proc. Natl. Acad. Sci. U. S. A., 73 (1976) 2424-2426]. Exposure to both ranges of magnetic fields (4.35-8.25 and 8.25-15.8 microT) has no effect on cell division. Thus, there is no evidence in this study that there is a mitogenic effect arising from low EMF exposure.
研究了低强度电磁场（EMF）暴露（4.5 - 15.8微特斯拉，50赫兹交流电）对大鼠嗜铬细胞瘤PC12细胞神经突生长和细胞分裂的影响。该研究包括两个独立的实验系列，其中暴露于磁场期间的培养条件有所不同。在系列1（14个实验，培养条件对细胞分化的促进作用不强[15%血清]）中，暴露于4.5 - 8.25微特斯拉23小时显著抑制神经突生长，抑制率为21.5±1.3%（通过多变量方差分析，p = 0.003）。相比之下，在系列2（12个实验，培养条件促进细胞分化[4%血清]）中，暴露于4.35 - 8.25微特斯拉23小时显著刺激神经突生长，增长率为16.9±1.1%（通过多变量方差分析，p = 0.009）。因此，在两个系列中，暴露于窄范围的低强度电磁场对神经突生长有显著但相反的影响。暴露于更高强度的磁场，8.25 - 12.5微特斯拉（系列1）和8.25 - 15.8微特斯拉（系列2）对神经突生长没有显著影响。这些数据与其他报告一起表明，低水平的电磁场暴露可能会改变神经元分化。虽然这可能无害，但值得进一步研究。目前，神经突生长显著变化局限于相同窄场强范围的原因尚不清楚。如上所述，系列2中的培养条件比系列1更有利于细胞分化。这体现在23小时孵育结束时，系列2对照样本中的细胞数量比系列1少（-16.9±1.7%，p = 0.003）。由于两个系列接种的细胞数量相同，系列1中使用的培养基能使更多PC12细胞分裂；这与一些细胞恢复到非神经元肾上腺嗜铬细胞表型一致[L. 格林，A. Tischler。建立对神经生长因子有反应的大鼠肾上腺嗜铬细胞瘤细胞的去甲肾上腺素能克隆系。美国国家科学院院刊，73（1976）2424 - 2426]。暴露于两个磁场范围（4.35 - 8.25和8.25 - 15.8微特斯拉）对细胞分裂没有影响。因此，本研究中没有证据表明低强度电磁场暴露会产生促有丝分裂作用。
