Exposure of rat brain to 915 MHz GSM microwaves induces changes in gene expression but not double stranded DNA breaks or effects on chromatin conformation

Abstract

We investigated whether exposure of rat brain to microwaves (MWs) of global system for mobile communication (GSM) induces DNA breaks, changes in chromatin conformation and in gene expression. An exposure installation was used based on a test mobile phone employing a GSM signal at 915 MHz, all standard modulations included, output power level in pulses 2 W, specific absorption rate (SAR) 0.4 mW/g. Rats were exposed or sham exposed to MWs during 2 h. After exposure, cell suspensions were prepared from brain samples, as well as from spleen and thymus. For analysis of gene expression patterns, total RNA was extracted from cerebellum. Changes in chromatin conformation, which are indicative of stress response and genotoxic effects, were measured by the method of anomalous viscosity time dependencies (AVTD). DNA double strand breaks (DSBs) were analyzed by pulsed-field gel electrophoresis (PFGE). Effects of MW exposure were observed on neither conformation of chromatin nor DNA DSBs. Gene expression profiles were obtained by Affymetrix U34 GeneChips representing 8800 rat genes and analyzed with the Affymetrix Microarray Suite (MAS) 5.0 software. In cerebellum from all exposed animals, 11 genes were upregulated in a range of 1.34-2.74 fold and one gene was downregulated 0.48-fold (P < .0025). The induced genes encode proteins with diverse functions including neurotransmitter regulation, blood-brain barrier (BBB), and melatonin production. The data shows that GSM MWs at 915 MHz did not induce PFGE-detectable DNA double stranded breaks or changes in chromatin conformation, but affected expression of genes in rat brain cells.

Histopathological examinations of rat brains after long-term exposure to GSM-900 mobile phone radiation

“…The animals are exposed to RF EMFs in the same TEM-cells (Figure 1 Belyaev et al [5]. These TEM-cells have been designed by dimensional scaling from previously constructed cells at the National Bureau of Standards [6], which are known to generate uniform TEM-fields for standard measurements.…”

Effect of Ultrahigh Frequency Radiation Emitted from 2G Cell Phone on Developing Lens of Chick Embryo: A Histological Study

“…The exposure of human lens epithelial cells (HLEC) to microwaves of 1800 MHz resulted in repairable DNA damage [9,18]. However, some studies have shown absence of DNA damage in human lymphocyte and leukocyte culture on exposure to RFR emitted from cell phone [19][20][21] and in rat brain exposed to 915 MHz GSM microwaves [22,23].…”

Genome-wide Response of Normal WI-38 Human Fibroblast Cells to 1,763 MHz Radiofrequency Radiation

“…It is clear that ionizing radiation, such as X-ray, affects biological systems, while it is still unclear and inconclusive whether non ionizing low-energy RF radiation could have effects on them. Although there have been a lot of studies of RF effects on biological systems for various aspects, most of them have focused on stress proteins, such as HSP, and MAPK signaling or DNA damages (Belyaev et al, 2006;Chauhan et al, 2006;Friedman et al, 2007;Lee et al, 2006;Sanchez et al, 2007;Sanchez et al, 2008, Verschaeve et al, 2009. For instance, Friedman et al (2007) found that exposure of HeLa and Rat1 cells to 875 MHz RF radiation induces the activation of the ERK cascade through ROS generation via NADH oxidase but not that of JNKs or p38 MAPKs.…”

“…Although most studies on the biological effects of RF exposure could not detect any molecular changes, some reports demonstrated RF-specific gene expression (Belyaev et al, 2006;Lee et al, 2005;Nylund et al, 2006). For example, Lee et al (2005) used the serial analysis of gene expression (SAGE) technique and found that 2.45 GHz RF radiation at a 10-W/kg SAR for 2∼6 h affected the expression of 221 genes, including apoptosis-related genes and cell cycle genes, in human HL-60 cells without a significant increase of HSP expression.…”