ROS release and Hsp70 expression after exposure to 1,800 MHz radiofrequency electromagnetic fields in primary human monocytes and lymphocytes
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The aim of this study is to investigate if 1,800 MHz radiofrequency electromagnetic fields (RF-EMF) can induce reactive oxygen species (ROS) release and/or changes in heat shock protein 70 (Hsp70) expression in human blood cells, using different exposure and co-exposure conditions. Human umbilical cord blood-derived monocytes and lymphocytes were used to examine ROS release after exposure to continuous wave or different GSM signals (GSM-DTX and GSM-Talk) at 2 W/kg for 30 or 45 min of continuous or intermittent (5 min ON/5 min OFF) exposure. The cells were exposed to incubator conditions, to sham, to RF-EMF, or to chemicals in parallel. Cell stimulation with the phorbol ester phorbol-12-myristate-13-acetate (PMA; 1 μM) was used as positive control for ROS release. To investigate the effects on Hsp70 expression, the human monocytes were exposed to the GSM-DTX signal at 2 W/kg for 45 min, or to heat treatment (42°C) as positive control. ROS production and Hsp70 expression were determined by flow cytometric analysis. The data were compared to sham and/or to control values and the statistical analysis was performed by the Student’s t-test (P<0.05). The PMA treatment induced a significant increase in ROS production in human monocytes and lymphocytes when the data were compared to sham or to incubator controls. After continuous or intermittent GSM-DTX signal exposure (2 W/kg), a significantly different ROS production was detected in human monocytes if the data were compared to sham. However, this significant difference appeared due to the lowered value of ROS release during sham exposure. In human lymphocytes, no differences could be detected if data were compared either to sham or to incubator control. The Hsp70 expression level after 0, 1, and 2 h post-exposure to GSM-DTX signal at 2 W/kg for 1 h did not show any differences compared to the incubator or to sham control.
KeywordsReactive Oxygen Species Production Human Monocyte Hsp70 Expression Specific Absorption Rate Incubator Control
We thank J. Schuderer and D. Spät from IT’IS, Zürich, Switzerland, for the technical analysis and decoding the blinded data of RF exposure. We are grateful to Prof. Dr E. Koepcke and his team from the Südstadt Clinic Center, Rostock (Germany) for providing the human umbilical cord blood and S. Hannemann for technical help during the flow cytometry analysis. This work is supported by the Federal Office for Radiation Protection, Salzgitter, Germany and is a part of the German Mobile Phone Research Program.
- 7.Kwee S, Raskmark P (1998) Radiofrequency electromagnetic fields and cell proliferation. In: Bersani F (ed) Electricity and magnetism in biology and medicine. Plenum, New York, pp. 187–190Google Scholar
- 10.Capri M, Scarcella E, Fumelli C, Bianchi E, Salvioli S, Mesirca P, Agostini C, Antolini A, Schiavoni A, Castellani G, Bersani F, Franceschi C (2004) In vitro exposure of human lymphocytes to 900 MHz CW and GSM modulated radiofrequency: studies of proliferation, apoptosis and mitochondrial membrane potential. Radiat Res 162:211–218CrossRefGoogle Scholar
- 18.Caraglia M, Marra M, Mancinelli F, D’ambrosio G, Massa R, Giordano A, Budillon A, Abbruzzese A, Bismuto E (2005) Electromagnetic fields at mobile phone frequency induce apoptosis and inactivation of the multi-chaperone complex in human epidermoid cancer cells. J Cell Physiol 204:539–548CrossRefGoogle Scholar
- 20.Gordon SA, Hoffman RA, Simmons RL, Ford HR (1997) Induction of heat shock protein 70 protects thymocytes against radiation-induced apoptosis. Arch Surg 132:1277–1282Google Scholar
- 26.Rollwitz J, Lupke M, Simkó M (2004) 50 Hz magnetic fields induce free radical formation in mouse bone marrow-derived promonocytes and macrophages. Biochim Biophys Acta 1674:231–238Google Scholar
- 28.Daniells C, Duce I, Thomas D, Sewell P, Tattersall J, de Pomerai D (1998) Transgenic nematodes as biomonitors of microwave-induced stress. Mutat Res 399:55–65Google Scholar
- 30.Kwee S, Raskmark P, Velizarov S (2001) Changes in cellular proteins due to environmental non-ionizing radiation, I. Heat shock proteins. Electromagnetobiology 20:1061–1072Google Scholar
- 31.Capri M, Scarcella E, Bianchi E, Fumelli C, Mesirca P, Agostini C, Remondini D, Schuderer J, Kuster N, Franceschi C, Bersani F (2004) 1800 MHz radiofrequency (mobile phones, different Global System for Mobile communication modulations) does not affect apoptosis and heat shock protein 70 level in peripheral blood mononuclear cells from young and old donors. Int J Radiat Biol 80:389–397CrossRefGoogle Scholar
- 33.Simkó M, Hartwig C, Lantow M, Lupke M, Mattsson MO, Rahman Q, Rollwitz J (2006) Hsp 70 expression and free radical release after exposure to non-thermal radio-frequency electromagnetic fields and ultrafine particles in human Mono Mac 6 cells. Toxicol Lett 161:73–82Google Scholar