Influence of Radiofrequency Radiation on Chromosome Aberrations in CHO Cells and Its Interaction with DNA-Damaging Agents

Abstract

A limited number of contradictory reports have appeared in the literature about the ability of radiofrequency (rf) radiation to induce chromosome aberrations in different biological systems. The technical documentation associated with such reports is often absent or deficient. In addition, no information is available as to whether any additional genotoxic hazard would result from a simultaneous exposure of mammalian cells to rf radiation and a chemical which (by itself) induces chromosome aberrations. In the work described, we have therefore tested two hypotheses. The first is that rf radiation by itself, at power densities and exposure conditions which are higher than is consistent with accepted safety guidelines, can induce chromosome aberrations in mammalian cells. The second is that, during a simultaneous exposure to a chemical known to be genotoxic, rf radiation can affect molecules, biochemical processes, or cellular organelles, and thus result in an increase or decrease in chromosome aberrations. Mitomycin C (MMC) and Adriamycin (ADR) were selected because they act by different mechanisms, and because they might put normal cells at risk during combined-modality rf radiation (hyperthermia)-chemotherapy treatment of cancer. The studies were performed with suitable 37 degrees C and equivalent convection heating-temperature controls in a manner designed to discriminate between any thermal and possible nonthermal action. Radiofrequency exposures were conducted for 2 h under conditions resulting in measurable heating (a maximum increase of 3.2 degrees C), with pulsed-wave rf radiation at a frequency of 2450 MHz and an average net forward power of 600 W, resulting in an SAR of 33.8 W/kg. Treatments with MMC or ADR were for a total of 2.5 h and encompassed the 2-h rf radiation exposure period. The CHO cells from each of the conditions were subsequently analyzed for chromosome aberrations. In cells exposed to rf radiation alone, and where a maximum temperature of approximately 40 degrees C was achieved in the tissue culture medium, no alteration in the frequency from 37 degrees C control levels was observed. Relative to the chemical treatment with MMC alone at 37 degrees C, for two different concentrations, no alteration was observed in the extent of chromosome aberrations induced by either simultaneous rf radiation exposure or convection heating to equivalent temperatures. At the ADR concentration that was used, most of the indices of chromosome aberrations which were scored indicated a similar result.(ABSTRACT TRUNCATED AT 400 WORDS)

Cytogenetic analysis of the effects of 2.5 and 10.5 GHz microwaves on human lymphocytes

“…In addition, cell phone radiation can alter protooncogene activity (Ivaschuk et al, 1997;Goswami et al, 1999). However, a similar number of studies have failed to detect obvious clastogenic effects following microwave irradiation of isolated animal cells in vitro (Alam et al, 1978;Lloyd et al, 1984Lloyd et al, , 1986Wolff et al, 1985;Meltz et al, 1987Meltz et al, , 1989Meltz et al, , 1990Kerbacher et al, 1990;Maes et al, 1997Maes et al, , 2001. Thus, there is still no conclusive answer as to whether exposure to microwaves is clastogenic, i.e., whether they can direct or indirectly increase the frequency of chromosomal aberrations.…”

Lack of alterations on meiotic chromosomes and morphological characteristics of male germ cells in mice exposed to a 60 Hz and 2.0 mT magnetic field

“…In vitro investigations of Kerbacher et al [1990] and Meltz et al [1990] on different cell systems provided evidence for a lack of direct genotoxic and mutagenic effects of continuous and pulsed microwaves at different power densities; furthermore, no synergistic effect was found between the applied field and Mitomycin-C, Adrianmycin, and Proflavin. Ciaravino et al [1991] also found no synergistic effect between moderate power radio frequency electromagnetic radiation and Adriamycin on cell cycle progression and sister chromatid exchanges.…”

Genotoxic effects of 3 T magnetic resonance imaging in cultured human lymphocytes

“…However, most of these studies did not make any definite statements about genotoxic and co-genotoxic effects of RF-EMF, and stated that further research is needed [Li et al, 2001;Meltz, 2003;Verschaeve et al, 2006]. Temperature elevation due to high SAR levels is one of the most established putative mechanisms leading to genotoxic effects by RF radiation [Kerbacher et al, 1990], and most studies have shown genotoxic and cogenotoxic effects of RF radiation at high SAR values (>3 W/kg). In this study, the human lymphocytes placed in the MRI scan were only exposed to SAR values below 3 W/kg and the sample temperature was controlled.…”