Biological responses to extremely low-frequency electromagnetic fields

Abstract

During the past decade, the biological effects of extremely low-frequency (ELF) electromagnetic fields have been investigated in many countries. Also, many papers for the responses to ELF electromagnetic fields had been published in both in vitro and in vivo . I review the cellular and molecular effects and mouse skin tumorigenesis of ELF electromagnetic fields. Cellular genotoxicity including chromosomal aberrations, DNA stand breaks, and mutation and the skin tumorigenesis in mice were examined using the conventional experimental methods. It is considered that sole exposure to ELF electromagnetic fields at an intensity of less than several hundred microtesla (μT) may not affect cell growth, cellular genotoxicity (such as DNA strand breaks, chromosome aberrations, mutations), gene expression, and signal transduction. However, exposure to ELF electromagnetic fields at an extremely high intensity, i.e., 400 mT, can induce chromatid-type aberrations, mutations, and induce expression of specific genes (NOR-1). Exposure to ELF electromagnetic fields at relatively high intensity (>several mT) may also potentiate the cellular damage induced by external factors, such as ionizing radiation and several chemical agents. In a recent animal study, it was reported that exposure to 50 Hz magnetic fields enhanced the rate of UV-induced tumor development in mouse skin It is unlikely that exposure to extremely low-density ELF electromagnetic fields at microtesla levels would evoke large changes in cells. However, many unclear issues remain to be resolved. The possible mechanisms of action of ELF electromagnetic fields are discussed.