Non-thermal effects of power-line magnetic fields (50 Hz) on gene expression levels of pluripotent embryonic stem cells—the role of tumour suppressor p53

• Published in: Mutation research Vol. 557; no. 1; pp. 63 - 74
• Main Authors: Czyz, Jaroslaw, Nikolova, Teodora, Schuderer, Jürgen, Kuster, Niels, Wobus, Anna M.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 10.01.2004; Elsevier
• Subjects: Animals; Biological and medical sciences; Cells, Cultured; Differentiation; Electromagnetic Fields; Embryo, Mammalian - cytology; Fundamental and applied biological sciences. Psychology; Gene Expression Regulation - radiation effects; Genes, Regulator; Genetics of eukaryotes. Biological and molecular evolution; Medical sciences; Mice; Mouse embryonic stem cells; Non-thermal effect; p53; Pluripotent Stem Cells - metabolism; Pluripotent Stem Cells - radiation effects; Toxicology; Tumor Suppressor Protein p53 - physiology; PL-MF; MTG; RT; IEC; egr-1; Electromagnetic fields; ES; Mouse embryonic stem cells; p53; IMDM; DMEM; hsp70; NEAA; RT-PCR; FCS; Non-thermal effect; Differentiation; EB; wt; β-ME; ELF; EMF; Stem cell; Rodentia; Gene expression; Vertebrata; Toxicology; Mammalia; TP53 Gene; Mouse; Embryonic cell; Genetics; Electromagnetic field; Magnetic field
• ISSN: 1383-5718; 0027-5107; 1879-3592
• DOI: 10.1016/j.mrgentox.2003.09.011

The diffusion of extremely low-frequency (50 Hz) electromagnetic fields (ELF-EMF) in the human environment raises the question of the induction of biological effects of EMF on mammalian cells. We used the model of mouse pluripotent embryonic stem (ES) cells, which have the capacity to develop in vitro into cells of all lineages, to analyse non-thermal effects of ELF-EMF. Wild type (wt) and p53-deficient ES cells were exposed under controlled conditions to ELF-EMF signals simulating power-line (50 Hz) magnetic field (PL-MF) exposure. Different flux densities of 0.1 mT, 1.0 mT or 2.3 mT and intermittency schemes with various ON/OFF cycles were applied for 6 h or 48 h during the first stages of cell differentiation. Transcript levels of regulatory genes, such as egr-1, p21, c- jun, c- myc, hsp70 and bcl-2, were analysed by semi-quantitative RT-PCR immediately after exposure or after a recovery time of 18 h. Intermittent PL-MF exposure to 5 min ON/30 min OFF cycles at a flux density of 2.3 mT for 6 h resulted in a significant up-regulation of c-jun, p21 and egr-1 mRNA levels in p53-deficient, but not in wild-type cells. No significant effects were observed in both cell systems by PL-MF at lower flux densities, longer exposure time or after 18 h recovery time. Our data indicate that 5 min ON/30 min OFF intermittent PL-MF exposure is capable of evoking non-thermal responses in ES cells, dependent on the cellular p53 function. The nature of the biological responses triggered by PL-MF is discussed.