Article

[Effect of 1.8 GHz radiofrequency electromagnetic fields on the expression of microtubule associated protein 2 in rat neurons]

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Abstract

To investigate the changes of gene expression in rat neurons induced by 1.8 GHz radiofrequency electromagnetic fields (RF EMF) and to screen for the RF EMF-responsive genes. Newly-born SD rats in 24 hours were sacrificed to obtain cortex and hippocampus neurons. The cells were divided randomly into two groups: the experiment group (the irradiation group) and the control group (the false irradiation group). In the irradiation group, after twelve days' culture, neurons were exposed to 1.8 GHz RF EMF modulated by 217 Hz at a specific absorption rate (SAR) of 2 W/kg for 24 hours (5 minutes on/10 minutes off) while in the false control group, the neurons were put in the same waveguide as in the irradiation group, but were not exposed to any irradiation. The total RNA was isolated and purified immediately after exposure. The affymetrix rat neurobiology U34 assay was used for detecting the changes in gene expression profile according to the manufacturer's instruction. RF EMF-responsive candidate gene was confirmed by using ribonuclease protection assay (RPA). Among 1200 candidate genes, the expression levels of 34 genes were up or down regulated. Microtubule associated protein 2 (Map2) gene was selected as the candidate and subjected to further analysis. RPA data clearly revealed that Map2 was statistically significantly up-regulated after neurons were exposed to the RF EMF (P < 0.05). The modulation of gene expression and function of Map2 as a neuron specific cytoskeleton protein is crucial to maintain the normal framework and function of neurons. The finding that 1.8 GHz RF EMF exposure increases the expression of Map2 might indicate some unknown effects of RF EMF on neurons.

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... Findings of sub-cellular and cellular changes induced by mobile phone radiation have been requested (Stewart 2000). In a series of recent publications, the influence of RF of the type emitted in GSM has been studied in different cell cultures, proving effects upon gene expression in cultured human cells (Czyz et al. 2004, Lee et al. 2005, Pacini et al. 2002, Remondini et al. 2006), rat neurons (Zhao et al. 2006 and), and mouse embryonic stem cells (Nikolova et al. 2005 ) through non-thermal mechanisms . In other studies, no gene expression alterations have been demonstrated in connection to GSM exposure, for example no changes in the gene expression in human glioblastoma cells (Qutob et al. 2006 ) or in human neuroblastoma cell lines (Gurisik et al. 2006). ...
... Indeed, it has been demonstrated that RFs of the type emitted by GSM mobile phones have effects upon gene expression in cultured human cells through nonthermal mechanisms; in skin fibroblasts (Pacini et al.Table 2 Significantly altered gene ontology categories in hippocampus in GSM versus sham-exposed rats (p \ 2 9 10 2002 ); in embryonic stem cells deficient of the p53 suppressor protein (Czyz et al. 2004); in HL-60 cells (Lee et al. 2005); in endothelial cell lines (Nylund and Leszczynnski 2006); and in lymphoblastoma cells, HL-60 cells and endothelial cells (Remondini et al. 2006). Also in cells from rodents, alterations of gene expression after GSM mobile phone exposure have been found; in rat neurons from cortex and hippocampus (Zhao et al. 2006); in mouse embryonic stem cell-derived neural progenitors (Nikolova et al. 2005); in mouse neurons and astrocytes (Zhao et al. 2007). In other cases, no effects on the gene expression have been observed after GSM exposure, such as in human glioblastoma cells (Qutob et al. 2006 ), in human neuroblastoma cell lines (Gurisik et al. 2006). ...
Article
Full-text available
We have earlier shown that radio frequency electromagnetic fields can cause significant leakage of albumin through the blood–brain barrier of exposed rats as compared to non-exposed rats, and alsosignificant neuronal damage in rat brains several weeks after a 2h exposure to a mobile phone, at 915MHz with a global system for mobile communications (GSM) frequency modulation, at whole-body specific absorption rate values (SAR) of 200, 20, 2, and 0.2mW/kg. We have now studied whether 6h of exposure to the radiation from a GSM mobile test phone at 1,800MHz (at a whole-body SAR-value of 13mW/kg, corresponding to a brain SAR-value of 30mW/kg) has an effect upon the gene expression pattern in rat brain cortex and hippocampus—areas where we have observed albumin leakage from capillaries into neurons and neuronal damage. Microarray analysis of 31,099 rat genes, including splicing variants, was performed in cortex and hippocampus of 8 Fischer 344 rats, 4 animals exposed to global system for mobile communications electromagnetic fields for 6h in an anechoic chamber, one rat at a time, and 4 controls kept as long in the same anechoic chamber without exposure, also in this case one rat at a time. Gene ontology analysis (using the gene ontology categories biological processes, molecular functions, and cell components) of the differentially expressed genes of the exposed animals versus the control group revealed the following highly significant altered gene categories in both cortex and hippocampus: extracellular region, signal transducer activity, intrinsic to membrane, and integral to membrane.The fact that most of these categories are connected with membrane functions may have a relation to our earlier observation of albumin transport through brain capillaries.
... Findings of sub-cellular and cellular changes induced by mobile phone radiation have been requested (Stewart 2000). In a series of recent publications, the influence of RF of the type emitted in GSM has been studied in different cell cultures, proving effects upon gene expression in cultured human cells (Czyz et al. 2004, Lee et al. 2005, Pacini et al. 2002, Remondini et al. 2006, rat neurons (Zhao et al. 2006 and, and mouse embryonic stem cells (Nikolova et al. 2005) through non-thermal mechanisms. In other studies, no gene expression alterations have been demonstrated in connection to GSM exposure, for example no changes in the gene expression in human glioblastoma cells (Qutob et al. 2006) or in human neuroblastoma cell lines (Gurisik et al. 2006). ...
... GO:0031224 intrinsic to membrane 1.9 9 10 -13 6 19 1,961 GO:0004930 G-protein coupled receptor activity 1.7 9 10 -12 2 1 328 GO:0050874 organismal physiological process 3.9 9 10 -11 7 11 958 GO:0001584 rhodopsin-like receptor activity 1.6 9 10 -9 2 0 240 GO:0007186 G-protein coupled receptor protein signaling pathway 3.0 9 10 - 2002); in embryonic stem cells deficient of the p53 suppressor protein (Czyz et al. 2004); in HL-60 cells (Lee et al. 2005); in endothelial cell lines (Nylund and Leszczynnski 2006); and in lymphoblastoma cells, HL-60 cells and endothelial cells (Remondini et al. 2006). Also in cells from rodents, alterations of gene expression after GSM mobile phone exposure have been found; in rat neurons from cortex and hippocampus (Zhao et al. 2006); in mouse embryonic stem cell-derived neural progenitors (Nikolova et al. 2005); in mouse neurons and astrocytes (Zhao et al. 2007). In other cases, no effects on the gene expression have been observed after GSM exposure, such as in human glioblastoma cells (Qutob et al. 2006), in human neuroblastoma cell lines (Gurisik et al. 2006). ...
Article
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 Igor Y. Belyaev 1* , Catrin Baur‚us Koch 2, 3 , Olle Terenius 1 , Katarina Roxstr”m-Lindquist 1 , Johan Lid‚n 4 , Lars O. G. Malmgren 2 , Wolfgang Sommer 5 , Karin Dahlman-Wright 4 , Leif G. Salford 3 , Bertil R. R. Persson 2 , Mats Harms-Ringdahl 1 1 Department of Genetics, Microbiology and Toxicology, Stockholm University, Stockholm, Sweden 2 Department of Radiation Physics, Lund University Hospital, Lund, Sweden 3 Department of Neurosurgery, Lund University Hospital, Lund, Sweden. 4 Department of Biosciences, Karolinska Institutet, Huddinge, Sweden 5 Department of Neurotec, Karolinska Institutet, Stockholm, Sweden * Address for correspondence: Dr. Igor Y. Belyaev, Department of Genetics, Microbiology and Toxicology, Stockholm University S-106 91 Stockholm, Sweden, Tel: +46-8-16 41 08, FAX: +46-8-16 43 15 E-mail: Igor.Belyaev@gmt.su.se Running title: Microwaves induce gene expression changes in brain The Swedish Council for Working Life and Social Research, the Swedish Authority for Radiation Protection and the Alice and Knut Wallenberg Foundation supported this study. 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 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 absorbed rate (SAR) 0.4 mW/g was used. Rats were exposed or sham-exposed to microwaves 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 exposed animals, eleven genes were up-regulated in a range of 1.34 to 2.74 fold and one gene was down regulated 0.48 fold (p<0.0025). The induced genes encode proteins with diverse functions including neurotransmitter regulation, blood-brain barrier (BBB), and melatonin production. The data shows that GSM microwaves 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. GSM MICROWAVES INDUCE CHANGES IN PATTERN OF GENE EXPRESSION IN rat brain cells in vivo Igor Belyaev 1,5, *, Catrin Baur‚us Koch 2, Katarina Roxstr”m-Lindquist 3, Olle Terenius 3, Johan Lid‚n 4, Lars Malmgren 2, Bertil Persson 2, Leif Salford 5, Mats Harms-Ringdahl 1 1Department of Genetic and Cellular Toxicology, Stockholm University, Stockholm, Sweden 2Department of Radiation Physics, Lund University Hospital, Lund, Sweden 3Department of Genetics, Stockholm University, Stockholm, Sweden; 4Department of Biosciences, Karolinska Institutet, Huddinge, Sweden 5 Department of Neurosurgery, Lund University Hospital, Lund, Sweden. 5Department of Biophysics, Radiation Physics and Ecology, Moscow Engineering Physics Institute, Russia *Address for correspondence: Dr. Igor Y. Belyaev, Department of Genetic and Cellular Toxicology, Stockholm University S-106 91 Stockholm, Sweden, Tel: +46-8-16 41 08, FAX: +46-8-16 43 15 E-mail: Igor.Belyaev@genetics.su.se Running title: Microwaves induce changes in gene expression The Swedish Council for Working Life and Social Research, and the Swedish Authority for Radiation Protection supported these studies. Abstract Here, we investigated whether GSM microwaves induce DNA breaks, changes in chromatin conformation and in gene expression. An installation based on the test-mobile phone and employing GSM signal, 915 MHz, all standard modulations included, output power level, 2 W, SAR being 0.4 mW/g was used. Rats were exposed or sham-exposed to microwaves during 2 h. After exposure, rats were sacrificed and brains were dissected into gray matter and white matter. Cell suspensions were prepared from these samples, as well as from spleen and thymus. Small brains were frozen in RNAlater for extraction of RNA and analysis of gene expression patterns. The changes in chromatin conformation, which are indicative of stress response and genotoxic effects, were measured with the method of anomalous viscosity time dependencies (AVTD). DNA double strand breaks (DSBs) were analyzed by pulsed-field gel electrophoresis (PFGE). The level of mRNA expression was studied by gene microarrays using Affymetrix U34 GeneChips representing 8800 genes. The data were analyzed with the t-test and the Affymetrix Microarray Suite (MAS) 5.0 software. No effects of GSM exposure were observed on conformation of chromatin as studied by the AVTD method. No microwave-induced DNA DSBs were detected using PFGE in all four types of cells. Six samples from exposed and sham exposed groups, 3 versus 3, were selected for microarray analysis based on RNA quality control. Eleven genes were up regulated in all exposed animals and one gene was down regulated. These changes did not exceed 2.6-fold but were statistically significant in all 9 comparisons. The data showed that GSM microwaves did not induce DNA breaks and changes in chromatin conformation but affected expression of genes in rat brain cells under specific conditions of exposure. Key words: DNA DSB, chromatin, gene microarrays.
... Findings of sub-cellular and cellular changes induced by mobile phone radiation have been requested (Stewart 2000). In a series of recent publications, the influence of RF of the type emitted in GSM has been studied in different cell cultures, proving effects upon gene expression in cultured human cells (Czyz et al. 2004, Lee et al. 2005, Pacini et al. 2002, Remondini et al. 2006, rat neurons (Zhao et al. 2006 and, and mouse embryonic stem cells (Nikolova et al. 2005) through non-thermal mechanisms. In other studies, no gene expression alterations have been demonstrated in connection to GSM exposure, for example no changes in the gene expression in human glioblastoma cells (Qutob et al. 2006) or in human neuroblastoma cell lines (Gurisik et al. 2006). ...
... GO:0031224 intrinsic to membrane 1.9 9 10 -13 6 19 1,961 GO:0004930 G-protein coupled receptor activity 1.7 9 10 -12 2 1 328 GO:0050874 organismal physiological process 3.9 9 10 -11 7 11 958 GO:0001584 rhodopsin-like receptor activity 1.6 9 10 -9 2 0 240 GO:0007186 G-protein coupled receptor protein signaling pathway 3.0 9 10 - 2002); in embryonic stem cells deficient of the p53 suppressor protein (Czyz et al. 2004); in HL-60 cells (Lee et al. 2005); in endothelial cell lines (Nylund and Leszczynnski 2006); and in lymphoblastoma cells, HL-60 cells and endothelial cells (Remondini et al. 2006). Also in cells from rodents, alterations of gene expression after GSM mobile phone exposure have been found; in rat neurons from cortex and hippocampus (Zhao et al. 2006); in mouse embryonic stem cell-derived neural progenitors (Nikolova et al. 2005); in mouse neurons and astrocytes (Zhao et al. 2007). In other cases, no effects on the gene expression have been observed after GSM exposure, such as in human glioblastoma cells (Qutob et al. 2006), in human neuroblastoma cell lines (Gurisik et al. 2006). ...
Article
Exposure to Global System for Mobile Communications at 1800 MHz Significantly Changes Gene Expression in Rat Hippocampi and Cortex Leif G. Salford 1 , Henrietta Nittby 1 , Morten Krogh 2 , Gustav Grafstr”m 3 , Henrik Berlin 1 , Gustav Rehn 1 , Jacob L. Eberhardt 3 , Lars Malmgren 4 , Bertil R.R. Persson 3 and Bengt Widegren 5 . Departments of Neurosurgery 1 , Theoretical Physics 2 , Medical Radiation Physics 3 , Applied 4 Electronics and Tumour Immunology 5 , Lund University, the Rausing Laboratory and Lund University Hospital, S-22185, Lund, Sweden. (2007-02-14) Corresponding author: Leif G. Salford Dept. of Neurosurgery Lund University Hospital S-221 85 Lund, Sweden Telephone: 46-46-171270 Fax: 46-46-188150 E-mail: Leif.Salford@neurokir.lu.seRUNNING TITLE: GENE CHANGES AFTER MOBILE PHONE EXPOSURE KEY WORDS: blood-brain barrier, gene expression, gene ontology, microwaves, mobile phone ACKNOWLEDGEMENTS AND SPONSORS: We are grateful to Susanne Str”mblad and Catharina Blennow for excellent technical assistance. We acknowledge help with microarray labwork and analysis by Ann-Sofie Albrekt at the Microarray Resource Centre at Lund University. This study was supported by the Hans and M„rit Rausing Charitable Foundation and the Lund University Hospital Funds. ABBREVIATIONS: BBB Blood-brain barrier GO Gene Ontology GSM-1800 Global System for Mobile Communication at 1800 MHz
Conference Paper
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Life on earth was formed during billions of years, exposed to, and shaped by the original physical forces such as gravitation, cosmic irradiation, atmospheric electric fields and the terrestrial magnetism. The Schumann resonances at 7.4 Hz are an example of oscillations possibly important for life.¹⁾ The existing organisms are created to function in harmony with these forces. However, in the late 19th century mankind introduced the use of electricity, in the early 20th century long-wave radio and in the 1940-ies short-wave radio. High frequency RF was introduced in the 50-ies as FM and television and during the very last decades, microwaves of the modern communication society spread around the world. Today, however, one third of the world's population is owner of the microwave-producing mobile phones and an even larger number is exposed to the cordless RF emitting systems. To what extent are all living organisms affected by these, almost everywhere present radio frequency fields? And what will be the effects of many years of continuing exposure? Since 1988 our group has studied the effects upon the mammalian blood-brain barrier (BBB) in rats by non-thermal radio frequency electromagnetic fields (RF-EMF). These have been shown to cause significantly increased leakage of the rats' own blood albumin through the BBB of exposed rats, at energy levels of 1W/kg and below, as compared to non-exposed animals in a total series of about two thousand animals.²⁾⁻⁶⁾ One remarkable observation is the fact that the lowest energy levels, with whole-body average power densities below 10mW/kg, give rise to the most pronounced albumin leakage. If mobile communication, even at extremely low energy levels, causes the users' own albumin to leak out through the BBB, also other unwanted and toxic molecules in the blood, may leak into the brain tissue and concentrate in and damage the neurons and glial cells of the brain. In later studies we have shown that a 2-h exposure to GSM 915 MHz, at non-thermal SAR-values of 0.2, 2 and 200 mW/kg, gives rise to significant neuronal damage, seen not only 50 days after the exposure⁷⁾ but also after 28 days but not after 14 days. Albumin extravasations and uptake into neurons was enhanced after 14 days, but not after 28.⁸⁾ In our continued research, also the non-thermal effects on tissue structure and memory function of long-term exposure for 13 months are studied.⁹⁾ We have also performed micro-array analysis of brains from rats exposed to short term GSM both at 1,800 MHz and at 900MHz and have found significant effects upon gene expression of membrane associated genes as compared to control animals.10), 11) Most of our findings support that living organisms are affected by the non-thermal radio frequency fields. Some other studies agree while others find no effects.
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