Littérature scientifique sur le sujet « Bioindicator,electromagnetic fields, genotoxicity »

Modulated electromagnetic fields (wEMFs), as generated by modern communication technologies, have raised concerns about adverse health effects. The International Agency for Research on Cancer (IARC) classifies them as “possibly carcinogenic to humans” (Group 2B), yet, the underlying molecular mechanisms initiating and promoting tumorigenesis remain elusive. Here, we comprehensively assess the impact of technologically relevant wEMF modulations on the genome integrity of cultured human cells, investigating cell type-specificities as well as time- and dose-dependencies. Classical and advanced methodologies of genetic toxicology and DNA repair were applied, and key experiments were performed in two separate laboratories. Overall, we found no conclusive evidence for an induction of DNA damage nor for alterations of the DNA repair capacity in cells exposed to several wEMF modulations (i.e., GSM, UMTS, WiFi, and RFID). Previously reported observations of increased DNA damage after exposure of cells to GSM-modulated signals could not be reproduced. Experimental variables, presumably underlying the discrepant observations, were investigated and are discussed. On the basis of our data, we conclude that the possible carcinogenicity of wEMF modulations cannot be explained by an effect on genome integrity through direct DNA damage. However, we cannot exclude non-genotoxic, indirect, or secondary effects of wEMF exposure that may promote tumorigenesis in other ways.

Abstract Outbreaks of new infectious diseases are occurring with increasing frequency and consequences, including wildlife diseases and zoonoses. The increasing emergence of infectious pathogens has many causes, all related to increasing anthropogenic impacts on nature. Some studies show how exposure to fields can enhance or reduce cellular activity, with possible application implications in the field of biotechnology. The effects of magnetic fields at the cellular level in microbial cells may include cell viability and proliferation, apoptosis, morphological changes, changes in metabolic and enzymatic activities, changes in ion transport into the cell, and genotoxicity and changes in gene expression. The aim of this study was to determine the differences in the somatic response of pathogen cells used in biotechnological processes exposed to an alternating electromagnetic field with a constant frequency of 50 Hz in three variants of exposure time. It was found that stimulation with an alternating electromagnetic field affects the somatic responses of microorganisms represented by their growth. The responses of the studied microorganisms are also related to their morphology.

Electromagnetic fields (EMF) such as those from electric power transmission and distribution lines (50/60 Hz) have been associated with increased risk of childhood leukemia, cancer of the nervous system, and lymphomas. Severalin vitrostudies on EMF effects were performed to clarify the existing controversies, define the risks, and determine the possible mechanisms of adverse effects. In some of these reports, the effects were related to other mechanisms of carcinogenesis. Modification in cell proliferation was observed after EMF exposure and a few reports on cytotoxic effects have also been published. This limited review gives an overview of the current results of scientific research regardingin vitrostudies on the effects of power line frequency EMF, but also cell biological mechanisms and their potential involvement in genotoxicity and cytotoxicity are discussed. Cell cycle control and signal transduction processes are included to elucidate the biochemical background of possible interactions. Exposure to EMF has been also linked to the incidence of leukemia and other tumors in some epidemiological studies and is considered as “possibly carcinogenic to humans”, but there is no well-established biological mechanism that explains such a relation. Furthermore, EMF is also shown as a stimulus for immune relevant cells (e.g., macrophages) to release free radicals. It is known that chronic activation of macrophages is associated with the onset of phagocytosis and leads to increased formation of reactive oxygen species, which themselves may cause DNA damage and are suggested to lead to carcinogenesis. To demonstrate a possible interaction between EMF and cellular systems, we present a mechanistic model describing cell activation as a major importance for cellular response.

Aiming to investigate the possibility of electromagnetic fields (EMF) developed by nonionizing radiation to be a noxious agent capable of inducing genotoxicity to humans, in the current study we have investigated the effect of 910-MHz EMF in rat bone marrow. Rats were exposed daily for 2 h over a period of 30 consecutive days. Studying bone marrow smears from EMF-exposed and sham-exposed animals, we observed an almost threefold increase of micronuclei (MN) in polychromatic erythrocytes (PCEs) after EMF exposure. An induction of MN was also observed in polymorphonuclear cells. The induction of MN in female rats was less than that in male rats. The results indicate that 910-MHz EMF could be considered as a noxious agent capable of producing genotoxic effects.

Exposure to radiofrequency electromagnetic fields (RF-EMF) at the operating frequencies of different communication devices can cause various biological effects. However, there is a lack of studies on the oxidative stress response and genotoxicity in the honey bee (Apis mellifera) after exposure to RF-EMF. In this study, we investigated the oxidative stress and DNA damage in honey bee larvae situated in waxcomb cells, exposed to modulated RF-EMF 23 Vm-1. The glutathione S-transferase activity decreased, whereas the catalase activity increased significantly in the honey bee larvae upon RF-EMF exposure. Superoxide dismutase activity, the level of lipid peroxidation, and DNA damage were not statistically altered in exposed honey bee larvae when compared to the control group. These results suggest that the biological effects of modulated RF-EMF in honey bee larvae depend on the exposure design.

Genotoxic effects of radiofrequency (RF)/microwave (MW) electromagnetic fields, by using s tandard protocol of single cell gel electrophoresis (SCGE) or comet assay, were investigated in the coelomocytes of the bioindicator Eisenia fetida exposed to both laboratory and field experiments. In particular, laboratory treatments were performed by a TEM microstrip (900MHz – 0.20mW/Kg) to reproduce the characteristics of the waves generated by RF anthropic sources found on field. In order to assess the potential oxidative damage caused by microwave electromagnetic exposure, two base excision repair enzymes, i.e. endonuclase III (Endo III) and formamidopyrimidine DNA glycosylase (FPG) were used in combination with a modified comet assay protocol. In addition, DNA fragmentation of combinative exposure of ultraviolet rays C (UVC) alone and in combination with microwaves was also studied; in order to assess the influence of electromagnetic fields on DNA repair mechanisms of UVC, T4 endonuclease V (T4PDG) enzyme, which specifically induces single-stranded breaks in ultraviolet-irradiated DNA, was used. Finally, a fieldwork was conducted in three electromagnetic hot-spots in the city of Milan, Italy; in addition, a negative control site with a low electromagnetic field intensity was considered. Loss of DNA integrity was detected by using two main comet assay parameters, i.e. Tail Moment (TM) and Tail Moment Olive (TMO). Data showed an initial increase in TM and TMO (expressed as differences between Tail Moment or Tail Moment Olive from exposed and respective controls averages) after EMF treatments, resulting the highest after the first minutes of recovery ( TM: 6.63±0.70, immediately after exposure and TMO: 4.43±0.38, after 30 minutes, respectively). However, a transient genotoxic damage was observed at 2 hours from exposure (p<0.01). The results, after adding EndoIII and FPG, showed higher values of TM after the combinative treatment with the two repair enzymes compared with microwave exposure (p<0.05) at all times of recovery. Concerning UVC exposure, we observed the highest value of TM after 1 hour from the exposure (5.94±0.42) and a significant diminish after 2 hours (1.73±0.33). In addition, T4 endonuclease V was able to increase the number of breaks after the exposure to UVC radiation at t0, for the damage was approximately four-fold the level of breaks from ultraviolet radiation alone ( TM of 3.42±0.36 and 13.88±1.61, respectively). The combinative effect of UVC and microwave exposure showed significant lower levels of DNA damage than those of corresponding UVC groups at 1 hour of recovery (3.02±0.26 and 5.91±0.54, p<0.01 for TM, respectively). However, DNA fragmentation from UVC plus radiofrequency treatments was significantly higher (p<0.05) than those of the corresponding UVC groups for the following times of recovery. T4PDG did not affect MW-induced DNA breaks (p>0.05); conversely, the action of the repair enzyme was affected by the presence of RF after UV exposure, because TM, after the combinative exposure of the two physical agents, resulted lower than that found by adding T4 Endonuclease V after ultraviolet rays exposure alone (p<0.05). Finally, field exposures revealed a significant difference between negative controls and exposed animals in all the hot spots (p<0.01); a positive correlation (p<0.001, R2 =0.56) between electric values and genotoxic parameters was found and no relationship between DNA damage and other environmental parameters, considered under field conditions, was observed