We assessed genotoxic effects of intermediate frequency magnetic fields (MF) in vitro and in vivo. Rat primary astrocytes were exposed for 24 h to a 7.5 kHz MF at a magnetic flux density of 30 or 300 µT. Male C57BL/6 J mice were exposed continuously for 5 weeks to a 7.5 kHz MF at 12 or 120 μT, and blood samples were collected for the genotoxicity assays. To evaluate possible co-genotoxicity, the in vitro experiments included combined exposure with menadione (an agent that induces mitochondrial superoxide production and DNA damage) and methyl methanesulfonate (an alkylating agent). DNA damage and DNA repair (in vitro) were measured using the alkaline Comet assay and formation of micronuclei was assessed microscopically (in vivo) or using flow cytometry (in vitro). The results did not support genotoxicity or co-genotoxicity of 7.5 kHz MFs at magnetic flux densities up to 300 µT in vitro or in vivo. On the contrary, there was some evidence that exposure to 7.5 kHz MFs might reduce the level of genetic damage. Strongest indication of any biological effects was obtained from measurements of relative cell number, which was significantly and consistently increased after MF exposure in all in vitro experiments. Health implications of this finding are unclear, but it suggests that 7.5 kHz MFs may stimulate cell proliferation or suppress cell death.

我们评估了体外和体内中频磁场（MF）的遗传毒性作用。将大鼠原代星形胶质细胞在30 kHz或300 µT的磁通密度下暴露于7.5 kHz MF 24小时。将雄性C57BL / 6 J小鼠在12或120μT下连续暴露于7.5 kHz MF持续5周，并收集血样进行基因毒性试验。为了评估可能的共基因毒性，体外实验包括与甲萘醌（一种诱导线粒体超氧化物生成和DNA损伤的试剂）和甲磺酸甲酯（一种烷基化试剂）联合暴露。DNA损伤和DNA修复（体外）用碱性彗星实验测定，并用显微镜评估微核的形成（体内）或使用流式细胞仪（体外）。在体外或体内，当磁通密度高达300 µT时，结果不支持7.5 kHz MF的遗传毒性或共遗传毒性。相反，有证据表明，暴露于7.5 kHz MF可能会降低遗传损伤的水平。从相对细胞数的测量中获得了任何生物学效应的最强迹象，在所有体外实验中，MF暴露后该数量均显着且持续增加。该发现对健康的影响尚不清楚，但它表明7.5 kHz MF可能刺激细胞增殖或抑制细胞死亡。