Department of Experimental Medicine and Biochemical Sciences, University of Perugia, Perugia, Italy.
Int J Radiat Biol. 2010 Aug;86(8):701-10. doi: 10.3109/09553001003789588.
The question of whether exposure to extremely low frequency magnetic fields (ELF-MF), may contribute to cerebral cancer and neurodegeneration is of current interest. In this study we investigated whether exposure to ELF-MF (50 Hz-1 mT) harms cerebral DNA and induces expression of 70-kDa heat shock protein (hsp70).
CD1 mice were exposed to a MF (50 Hz-1 mT) for 1 or 7 days (15 h/day) and sacrificed either at the end of exposure or after 24 h. Unexposed and sham-exposed mice were used as controls. Mouse brains were dissected into cerebral cortex-striatum, hippocampus and cerebellum to evaluate primary DNA damage and hsp70 gene expression. Food intake, weight gain, and motor activity were also evaluated.
An increase in primary DNA damage was detected in all cerebral areas of the exposed mice sacrificed at the end of exposure, as compared to controls. DNA damage, as can be evaluated by the comet assay, appeared to be repaired in mice sacrificed 24 h after a 7-day exposure. Neither a short (15 h) nor long (7 days) MF-exposure induced hsp70 expression, metabolic and behavioural changes.
These results indicate that in vivo ELF-MF induce reversible brain DNA damage while they do not elicit the stress response.
目前人们关注的问题是，极低频磁场（ELF-MF）暴露是否会导致脑癌和神经退行性变。在这项研究中，我们研究了 ELF-MF（50 Hz-1 mT）暴露是否会损害大脑 DNA 并诱导 70-kDa 热休克蛋白（hsp70）的表达。
CD1 小鼠接受 MF（50 Hz-1 mT）暴露 1 或 7 天（每天 15 小时），并在暴露结束时或暴露后 24 小时处死。未暴露和假暴露的小鼠用作对照。将小鼠大脑解剖为大脑皮层-纹状体、海马体和小脑，以评估初级 DNA 损伤和 hsp70 基因表达。还评估了食物摄入、体重增加和运动活动。
与对照组相比，在暴露结束时处死的暴露小鼠的所有大脑区域均检测到初级 DNA 损伤增加。如彗星试验评估的那样，在接受 7 天暴露后 24 小时处死的小鼠中，DNA 损伤似乎得到了修复。短时间（15 小时）或长时间（7 天）MF 暴露均未诱导 hsp70 表达、代谢和行为变化。
这些结果表明，体内 ELF-MF 可引起可逆的大脑 DNA 损伤，而不会引起应激反应。
