Department of Research-BEM, IRYCIS, Hospital Ramon y Cajal, 28034 Madrid, Spain.
Oncol Rep. 2013 Mar;29(3):885-94. doi: 10.3892/or.2012.2212. Epub 2012 Dec 24.
We previously reported that intermittent exposure to a 50‑Hz magnetic field (MF) at 100 µT stimulates cell proliferation in the human neuroblastoma cell line NB69. The present study aimed to investigate whether the magnetic field-induced growth promotion also occurs at a lower magnetic flux density of 10 µT. To this purpose, NB69 cells were subjected for 42 h to intermittent exposure, 3 h on/3 h off, to a 50‑Hz MF at a 10 or 100 µT magnetic flux density. The field exposure took place either in the presence or in the absence of the antiproliferative agent retinoic acid. At the end of the treatment and/or incubation period, the cell growth was estimated by hemocytometric counting and spectrophotometric analysis of total protein and DNA contents. Potential changes in DNA synthesis were also assessed through proliferating cell nuclear antigen (PCNA) immunolabeling. The results confirmed previously reported data that a 42-h exposure to a 50‑Hz sine wave MF at 100 µT promotes cell growth in the NB69 cell line, and showed that 10 µT induces a similar proliferative response. This effect, which was significantly associated and linearly correlated with PCNA expression, was abolished by the presence of retinoic acid in the culture medium.
我们之前曾报道，间歇性暴露于 50Hz 磁场（MF）中 100µT 会刺激人神经母细胞瘤细胞系 NB69 的细胞增殖。本研究旨在探讨磁场诱导的生长促进作用是否也会在较低的磁通密度 10µT 下发生。为此，将 NB69 细胞暴露于 50Hz MF 中 42 小时，磁场强度为 10µT 或 100µT，每 3 小时开/关一次。磁场暴露要么在有抗增殖剂视黄酸的情况下进行，要么在没有视黄酸的情况下进行。在处理和/或孵育期结束时，通过血细胞计数和总蛋白和 DNA 含量的分光光度分析来估计细胞生长。还通过增殖细胞核抗原（PCNA）免疫标记评估 DNA 合成的潜在变化。结果证实了之前报道的数据，即在 100µT 的 50Hz 正弦波 MF 中暴露 42 小时会促进 NB69 细胞系的细胞生长，并表明 10µT 会引起类似的增殖反应。这种效应与 PCNA 表达显著相关且呈线性相关，在培养基中存在视黄酸时会被消除。
