Griffin G D, Williams M W, Gailey P C
Life Sciences Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6101, USA.
Radiat Res. 2000 May;153(5 Pt 2):690-8. doi: 10.1667/0033-7587(2000)153[0690:ccicce]2.0.co;2.
Magnetic-field exposure (45 Hz B(a.c.) over a flux density range of 7.7 to 49.9 microT r.m.s. with parallel B(d.c.) of 36.6 microT) has been reported by Blackman and coworkers to inhibit gap junction intercellular communication in Clone 9 cells treated with chloral hydrate for 24 h prior to field exposure in accord with predictions of the ion parametric resonance model. The study reported here is an attempt to reproduce this effect. Baseline experiments showed that growth in culture and state of confluence at time of addition of chloral hydrate were comparable in both laboratories. PMA inhibited cell-cell communication in a dose-dependent manner, similar to the results of Blackman and coworkers, whereas cells in the present study were somewhat more sensitive to chloral hydrate than reported by Blackman and coworkers. A total of 38 exposure experiments were undertaken using a 45 Hz magnetic field with a flux density of 23.8 microT r.m.s., in parallel with a 36.6-microT static magnetic field for 40 to 45 min, after pretreatment with 2.5 mM chloral hydrate for 24 h. In 14 unblinded experiments, a small but statistically significant effect of magnetic-field exposure was observed, but due to the subjective nature of the assay, it was deemed essential to carry out blinded experiments. The remaining 24 experiments were blinded. In 15 blinded experiments, cells purchased from the American Type Culture Collection and grown only in this laboratory were used, while in 9 experiments, the cells had originally been grown in Blackman's laboratory and were subsequently sent to this laboratory. There was no statistically significant effect of magnetic-field exposure on gap junction intercellular communication in these blinded experiments using either cell line.
布莱克曼及其同事报告称，磁场暴露（45赫兹交变磁场，均方根磁通密度范围为7.7至49.9微特斯拉，平行直流磁场为36.6微特斯拉）能够抑制水合氯醛处理24小时后的克隆9细胞中的间隙连接细胞间通讯，这与离子参数共振模型的预测相符。本文所报告的研究旨在重现这一效应。基线实验表明，两个实验室在添加水合氯醛时的细胞培养生长情况和汇合状态相当。佛波酯以剂量依赖方式抑制细胞间通讯，这与布莱克曼及其同事的结果相似，而本研究中的细胞对水合氯醛的敏感性略高于布莱克曼及其同事所报告的情况。在使用均方根磁通密度为23.8微特斯拉的45赫兹磁场、平行36.6微特斯拉静态磁场，持续40至45分钟，以及用2.5毫摩尔水合氯醛预处理24小时后，共进行了38次暴露实验。在14次未设盲的实验中，观察到磁场暴露有微小但具有统计学意义的效应，但由于检测方法的主观性，认为进行设盲实验至关重要。其余24次实验设盲。在15次设盲实验中，使用了从美国典型培养物保藏中心购买并仅在本实验室培养的细胞，而在9次实验中，细胞最初在布莱克曼实验室培养，随后被送到本实验室。在这些使用任一细胞系的设盲实验中，磁场暴露对间隙连接细胞间通讯均无统计学意义的影响。
