Effects of 2.45-GHz Electromagnetic Fields with a Wide Range of SARs on Micronucleus Formation in CHO-K1 Cells

S Koyama,Y Suzuki,M Taki,J Miyakoshi,Y Isozumi

doi:10.1100/tsw.2004.176

Abstract

There has been considerable discussion about the influence of high-frequency electromagnetic fields (HFEMF) on the human body. In particular, HFEMF used for mobile phones may be of great concern for human health. In order to investigate the properties of HFEMF, we have examined the effects of 2.45-GHz EMF on micronucleus (MN) formation in Chinese hamster ovary (CHO)-K1 cells. MN formation is induced by chromosomal breakage or inhibition of spindles during cell division and leads to cell damage. We also examined the influence of heat on MN formation, since HFEMF exposure causes a rise in temperature. CHO-K1 cells were exposed to HFEMF for 2 h at average specific absorption rates (SARs) of 5, 10, 20, 50, 100, and 200 W/kg, and the effects on these cells were compared with those in sham-exposed control cells. The cells were also treated with bleomycin alone as a positive control or with combined treatment of HFEMF exposure and bleomycin. Heat treatment was performed at temperatures of 37, 38, 39, 40, 41, and 42°C.The MN frequency in cells exposed to HFEMF at a SAR of lower than 50 W/kg did not differ from the sham-exposed controls, while those at SARs of 100 and 200 W/kg were significantly higher when compared with the sham-exposed controls. There was no apparent combined effect of HFEMF exposure and bleomycin treatment. On heat treatment at temperatures from 38–42°C, the MN frequency increased in a temperature-dependent manner. We also showed that an increase in SAR causes a rise in temperature and this may be connected to the increase in MN formation generated by exposure to HFEMF.

Highlights

In the modern era, people are exposed to many kinds of electromagnetic fields (EMF) and exposure occurs almost all day long
In a previous study on the effects of high-frequency electromagnetic fields (HFEMF) on MN formation in Chinese hamster ovary (CHO)-K1 cells, we showed that exposure to HFEMF at a SAR lower than 50 W/kg did not induce MN formation, but that a statistically significant increase in MN formation at SARs of 100 and 78 W/kg did occur[23]
There was no difference in MN formation in CHO-K1 cells exposed to HFEMF at a SAR lower than 50 W/kg, but there were statistically significant increases in MN frequency at SARs of 100 and 200 W/kg, compared with the sham-exposed control (Fig. 7)

Summary

Introduction

People are exposed to many kinds of electromagnetic fields (EMF) and exposure occurs almost all day long. Several epidemiological studies have indicated that exposure to EMF may be associated with an increased risk of childhood leukemia and other cancers[1,2,3,4], and this has caused great interest in the field. Some positive data have indicated a correlation between exposure to environmental low-frequency EMF and DNA damage or chromosomal aberrations, which may induce certain kinds of disease[5,6,7]. In addition to the conflicting and contradictory views on extremely low-frequency EMF, there is controversy surrounding the effects of high-frequency electromagnetic fields (HFEMF)[9,10]. HFEMF are used in mobile communication and, there is considerable interest in the possible effects of HFEMF on human health

Methods

Results

Conclusion