Analysis of DNA fragmentation in mouse embryos exposed to an extremely low-frequency electromagnetic field

Exposure to urban ambient particles (PM2.5) before pregnancy affects the expression of endometrial receptive markers to embryo implantation in mice: Preliminary results

Air pollution (AP) is one of the main recent concerns in reproductive healthy due to its potential to promote negative outcomes during pregnancy and male and female fertility. Several studies have demonstrated that AP exposure has been linked to increased embryonic implantation failures, alterations in embryonic, fetal and placental development. For a well-succeeded implantation, both competent blastocyst and receptive endometrium are required. Based on the lack of data about the effect of AP in endometrial receptivity, this study aimed to evaluate he particulate matter (PM) exposure impact on uterine receptive markers in mice and associate the alterations to increased implantation failures due to AP. For this study, ten dams per group were exposed for 39 days to either filter (F) or polluted air (CAP). At fourth gestational day (GD4), females were euthanized. Morphological, ultrastructural, immunohistochemical and molecular analysis of uterine and ovarian samples were performed. CAP-exposed females presented a reduced number of corpus luteum; glands and epithelial cells were increased with pinopodes formation impairment. Immunohistochemistry analysis revealed decreased LIF protein levels. These preliminary data suggests that PM exposure may exert negative effects on endometrial receptivity by affecting crucial parameters to embryonic implantation as uterine morphological differentiation, corpus luteum quantity and LIF expression during implantation window.

Cellular and molecular effects of non-ionizing electromagnetic fields

The way that living cells respond to non-ionizing electromagnetic fields (EMF), including static/extremely-low frequency and radiofrequency electromagnetic fields, fits the pattern of 'cellular stress response' - a mechanism manifest at the cellular level intended to preserve the entire organism. It is a set pattern of cellular and molecular responses to environmental stressors, such as heat, ionizing radiation, oxidation, etc. It is triggered by cellular macromolecular damage (in proteins, lipids, and DNA) with the goal of repairing and returning cell functions to homeostasis. The pattern is independent of the type of stressor encountered. It involves cell cycle arrest, induction of specific molecular mechanisms for repair, damage removal, cell proliferation, and cell death if damage is too great. This response could be triggered by EMF-induced alternation in oxidative processes in cells. The concept that biological response to EMF is a 'cellular stress response' explains many observed effects of EMF, such as nonlinear dose- and time-dependency, increased and decreased risks of cancer and neurodegenerative diseases, enhanced nerve regeneration, and bone healing. These responses could be either detrimental or beneficial to health, depending on the duration and intensity of the exposure, as well as specific aspects of the living organism being exposed. A corollary to electromagnetic hypersensitivity syndrome (EHS) could be an inappropriate response of the hippocampus/limbic system to EMF, involving glucocorticoids on the hypothalamic-pituitary-adrenal axis.

The role of non-ionizing electromagnetic radiation on female fertility: A review

With increasing technological developments, exposure to non-ionizing radiations has become unavoidable as people cannot escape from electromagnetic field sources, such as Wi-Fi, electric wires, microwave oven, radio, telecommunication, bluetooth devices, etc. These radiations can be associated with increased health problems of the users. This review aims to determine the effects of non-ionizing electromagnetic radiations on female fertility. To date, several in vitro and in vivo studies unveiled that exposure to non-ionizing radiations brings about harmful effects on oocytes, ovarian follicles, endometrial tissue, estrous cycle, reproductive endocrine hormones, developing embryo, and fetal development in animal models. Non-ionizing radiation also upsurges the free radical load in the uterus and ovary, which leads to inhibition of cell growth and DNA disruptions. In conclusion, non-ionizing electromagnetic radiations can cause alterations in both germ cells as well as in their nourishing environment and also affect other female reproductive parameters that might lead to infertility.

Cleavage of Early Mouse Embryo with Damaged DNA

The preimplantation period of embryogenesis is crucial during mammalian ontogenesis. During this period, the mitotic cycles are initiated, the embryonic genome is activated, and the primary differentiation of embryonic cells occurs. All cellular abnormalities occurring in this period are the primary cause of fetal developmental disorders. DNA damage is a serious cause of developmental failure. In the context of DNA damage response on the cellular level, we analyzed the course of embryogenesis and phenotypic changes during the cleavage of a preimplantation embryo. Our results document that DNA damage induced before the resumption of DNA synthesis in a zygote can significantly affect the preimplantation development of the embryo. This developmental ability is related to the level of the DNA damage. We showed that one-cell embryos can correct the first cleavage cycle despite low DNA damage and incomplete replication. It seems that the phenomenon creates a predisposition to a segregation disorder of condensed chromatin that results in the formation of micronuclei in the developmental stages following the first cleavage. We conclude that zygote tolerates a certain degree of DNA damage and considers its priority to complete the first cleavage stage and continue embryogenesis as far as possible.

Risk of congenital heart disease due to exposure to common electrical appliances during early pregnancy: a case-control study

To examine the association between exposure to common electrical appliances in early pregnancy and congenital heart disease (CHD). A case-control study of 2339 participants was conducted in six hospitals in Xi'an, Shaanxi Province, Northwest China from 2014 to 2016. All infants with CHD were diagnosed according to ICD-10 classification. Selected controls consisted of newborns from the same hospital, without any birth defects, and 1:3 matched by birthdate. We conducted personal interviews with the mothers to gather information on any exposure to electrical appliances during pregnancy. Multivariate logistic regression was used to estimate the effects of exposure to common electrical appliances on CHD. We observed that the mothers exposed to computers (OR: 1.33, 95% CI: 1.03, 1.71), induction cookers (OR: 2.79, 95% CI: 2.19, 3.55), and microwave ovens (OR: 1.53, 95% CI: 1.01, 2.31) during early pregnancy were more likely to give birth to infants with CHD. Mothers who wore radiation protection suits (OR: 0.67, 95% CI: 0.52, 0.87) during early pregnancy decreased the risk of CHD in their neonate. There was an interaction for induction cooker exposure with wore radiation protection suits on CHD (RERI: - 1.44, 95% CI: - 2.48, - 0.39; S: 0.37, 95% CI: 0.16, 0.84; AP: - 0.79, 95% CI: - 1.53, - 0.05). Our study confirmed that exposure to some electrical appliances was associated with a higher risk of CHD, and wearing a radiation protection suit was associated with a lower risk of CHD. Women should therefore reduce the usage of electrical appliances before and during pregnancy.

The Effect of Prenatal Exposure to 2.4 GHz Radio Frequency on the Histology and Expression of the osteocalcin and RUNX2 Gene of the Forelimb in an NMRI Mouse

Introduction: Today the use of electromagnetic waves has dramatically increased in modern industrial societies. This study aimed to investigate the effect of prenatal exposure to 2.4 GHz wireless frequency on forelimb development in an NMRI mouse in vivo. Methods: A total of 21 female mice weighing 25-30 g were included in the present study. They were randomly assigned to 3 groups, namely control (n=7), sham (n=7), and experimental (n=7). After mating, the experimental group was exposed to 2.4 GHz radio frequency at a distance of 20-30 cm from the device, 4 h/d until the delivery. The sham group was placed at a distance of 20-30 cm from the device every day without exposure to electromagnetic waves, and the control group had a pregnancy period without any stress and electromagnetic wave exposure. After giving birth, the forelimbs were isolated from the infants and examined by stereological studies and RT-PCR for the evaluation of osteocalcin and RUNX2 gene expression. Results: Although, at first glance, there was no macroscopic teratogen effect in forelimbs in all groups, via a stereological method, we showed that bone and cartilage volume decreased in the experimental group compared to the other groups. We also found that the experimental group had lower expression of the osteocalcin and RUNX2 gene than the control and sham groups did. However, there were no significant differences between the control and sham groups in terms of bone and cartilage volume and gene expression. Conclusion: Although teratogen effect of prenatal exposure to 2.4 GHz radio frequency on forelimbs was not demonstrated macroscopically, further studies showed negative effects on the forelimb bone, cartilage volume, and gene expression.

Effect of radiofrequency radiation on reproductive health

The development of cellular phone system has greatly increased the extent and magnitude of radiofrequency radiation (RFR) exposure. The RFR emitted from mobile phone and mobile phone base stations exerts thermal and non-thermal effects. The short-term and long-term exposure to RFR may have adverse effect on humans as well as animals. Most laboratory studies have indicated a direct link between exposure to RFR and adverse biological effects. Several in vitro studies have reported that RFR induces various types of cancer and DNA or chromosomal damage. On the other hand, some animal studies have not reported adverse effects of this radiation. The present review summarizes information available on the possible effects of RFR on the reproductive health.

Role of Mitochondria in the Oxidative Stress Induced by Electromagnetic Fields: Focus on Reproductive Systems

Modern technologies relying on wireless communication systems have brought increasing levels of electromagnetic field (EMF) exposure. This increased research interest in the effects of these radiations on human health. There is compelling evidence that EMFs affect cell physiology by altering redox-related processes. Considering the importance of redox milieu in the biological competence of oocyte and sperm, we reviewed the existing literature regarding the effects of EMFs on reproductive systems. Given the role of mitochondria as the main source of reactive oxygen species (ROS), we focused on the hypothesis of a mitochondrial basis of EMF-induced reproductive toxicity. MEDLINE, Web of Science, and Scopus database were examined for peer-reviewed original articles by searching for the following keywords: “extremely low frequency electromagnetic fields (ELF-EMFs),” “radiofrequency (RF),” “microwaves,” “Wi-Fi,” “mobile phone,” “oxidative stress,” “mitochondria,” “fertility,” “sperm,” “testis,” “oocyte,” “ovarian follicle,” and “embryo.” These keywords were combined with other search phrases relevant to the topic. Although we reported contradictory data due to lack of uniformity in the experimental designs, a growing body of evidence suggests that EMF exposure during spermatogenesis induces increased ROS production associated with decreased ROS scavenging activity. Numerous studies revealed the detrimental effects of EMFs from mobile phones, laptops, and other electric devices on sperm quality and provide evidence for extensive electron leakage from the mitochondrial electron transport chain as the main cause of EMF damage. In female reproductive systems, the contribution of oxidative stress to EMF-induced damages and the evidence of mitochondrial origin of ROS overproduction are reported, as well. In conclusion, mitochondria seem to play an important role as source of ROS in both male and female reproductive systems under EMF exposure. Future and more standardized studies are required for a better understanding of molecular mechanisms underlying EMF potential challenge to our reproductive system in order to improve preventive strategies.

Effects of Simulated Mobile Phone Electromagnetic Radiation on Fertilization and Embryo Development

This study investigated the effects of 935-MHz electromagnetic radiation (ER) on fertilization and subsequent embryonic development in mice. Ovulating mice were irradiated at three ER intensities for 4 h/day (d) or 2 h/d for three consecutive days; the ova were then harvested for in vitro fertilization to observe the 6-h fertilization rate (6-FR), 72-h morula rate (72-MR), and 110-h blastula rate (110-BR). Compared with the control group, the 6-FR, 72-MR, and 110-BR were decreased in the low ER intensity group, but the differences were not significant; in the mid- and high-intensity ER groups, 72-MR and 110-BR in the 4 h/d and 2 h/d subgroups were decreased, showing significant differences compared with the control group. Moreover, the comparison between 4 h/d and 2 h/d subgroups showed significant differences. Mid- and high-intensity ER at 935 MHz can reduce the fertilization rate in mice, and reduce the blastulation rate, thus reducing the possibility of embryo implantation.

A review on Electromagnetic fields (EMFs) and the reproductive system

Environmental factors, such as electromagnetic waves, induce biological and genetic effects. One of the most important physiological systems involved with electromagnetic fields (EMFs) is the genital system. This paper reviews the effects of EMFs on human reproductive organs, female animals, fetus development and the importance of two types of natural antioxidants, i.e., vitamin E and fennel. The studies presented in this review referred to the effects of different exposures to EMFs on the reproductive system, and we tried to show the role of natural antioxidants in reducing the effects of the exposures. Many studies have been done on the effects of ionizing and non-ionizing electromagnetic waves on the cell line of spermatogenesis, sexual hormones, and the structure of the testes. Also, about the hormonal cycle, folliculogenesis and female infertility related to EMF have been given more consideration. In particular, attention is directed to pregnant women due to the importance of their fetuses. However, in addition to the studies conducted on animals, further epidemiological research should be conducted.

Extremely Low Frequency Magnetic Fields Do Not Induce DNA Damage in Human Lens Epithelial Cells In Vitro

Non-ionizing radiations, e.g., radiofrequency electromagnetic fields, could induce DNA damage and oxidative stress in human lens epithelial cells (LECs) which can be early events in cataractogenesis. Extremely low frequency magnetic fields (ELF MF) as another common form of man-made electromagnetic fields has been considered as suspected human carcinogen by International Agency for Research on Cancer (IARC) and become a focus that people play more and more attentions to. This study aimed to determine whether ELF MF can induce DNA damage in cultured human LECs at a relatively low intensity. Human LECs were exposed or sham-exposed to a 50 Hz ELF MF which produced by a well-designed exposure system at the intensity of 0.4 mT. DNA damage in human LECs was examined by the phosphorylated form of histone variant H2AX (γH2AX) foci formation assay and further explored with western blot, flow cytometry, and alkaline comet assay. Immunofluorescence analysis showed that 0.4 mT ELF MF did not significantly increase γH2AX foci formation in human LECs after 2, 6, 12, 24, or 48 hr exposure. No significant differences had been detected in γH2AX expression level between the ELF MF- and sham-exposure groups, while no obvious chromosomal DNA fragmentation was detected by alkaline comet assay after ELF MF exposure. The results indicate an absence of genotoxicity in ELF MF-exposed human epithelial cells and do not support the hypothesis that environmental ELF MF might be causally led to genomic instability via chromosomal damage response processes. Neither short nor long term continuous exposure to 50 Hz ELF MF at 0.4 mT could induce DNA damage in human lens epithelial cells in vitro.

Extremely low-frequency magnetic fields induce developmental toxicity and apoptosis in zebrafish (Danio rerio) embryos

Extremely low-frequency (ELF) magnetic field (MF), as a widespread ecological factor, has an influence on all living beings. In the present study, biological effects of ELF-MF on the development of zebrafish (Danio rerio) embryos were investigated. Fertilized embryos were divided into seven groups as control, sham, and five experimental groups. Embryos of experimental groups were continuously exposed to 50-Hz sinusoidal MF with intensities of 30, 100, 200, 400, and 800 μT for 96 h. The sham group was treated as the experimental groups, but without any ELF-MF exposure. The control group was not subjected to anything. The results showed that ELF-MF exposure caused delayed hatching and decreased heart rate at the early developmental stages of zebrafish embryos, whereas no significant differences in embryo mortality and abnormality were observed. Moreover, acridine orange staining assays showed notable signals of apoptosis mainly in the ventral fin and spinal column. The transcription of apoptosis-related genes (caspase-3, caspase-9) was significantly upregulated in ELF-MF-exposed embryos. In conclusion, the overall results demonstrated that ELF-MF exposure has detrimental effects on the embryonic development of zebrafish by affecting the hatching, decreasing the heart rate, and inducing apoptosis, although such effects were not mortal threat. The results also indicate that zebrafish embryos can serve as a reliable model to investigate the biological effect of ELF-MF.

Effects of microwaves (950 MHZ mobile phone) on morphometric and apoptotic changes of rabbit epididymis

The effect of mobile phone radiation on human reproduction system is still a matter of debate. In this study, 18 male rabbits were randomly divided into two experimental groups and one control group. Experimental groups received simulated microwaves with the frequency of 950 MHz and the output power of 3 and 6 watts for 2 weeks, 2 h a day. After a week of rest, the microscopic slides from the quada of the excised epididymis were prepared. Then, the diameter of epididymis, the height of epithelium and the number of apoptotic cells in epithelium in study groups were determined. The data were compared using spss software and one-way anova test. The epithelial height and diameter of the epididymis in 3 watt and 6 watt groups had a significant decrease compared to the control group (P < 0.001), while the testosterone level only in 6 watt group was significantly decreased compared to control group. The rate of apoptosis in the epithelial cells of the epididymis had a significant increase only in 6 watt group compared to the control group (P < 0.001). This study showed that the microwaves with the frequency of 950 MHz can have negative impacts on morphometric and apoptotic changes of rabbit epididymis.

Laser microbeam-induced DNA damage inhibits cell division in fertilized eggs and early embryos

DNA double-strand breaks are caused by both intracellular physiological processes and environmental stress. In this study, we used laser microbeam cut (abbreviated microcut or cut), which allows specific DNA damage in the pronucleus of a fertilized egg and in individual blastomere(s) of an early embryo, to investigate the response of early embryos to DNA double-strand breaks. Line type γH2AX foci were detected in the cut region, while Chk2 phosphorylation staining was observed in the whole nuclear region of the cut pronuclei or blastomeres. Zygotes with cut male or female pronucleus showed poor developmental capability: the percentage of cleavage embryos was significantly decreased, and the embryos failed to complete further development to blastocysts. The cut blastomeres in 2-cell, 4-cell, and 8-cell embryos ceased cleavage, and they failed to incorporate into compacted morulae, but instead underwent apoptosis and cell death at the blastocyst stage; the uncut part of embryos could develop to blastocysts, with a reduced percentage or decreased cell number. When both blastomeres of the 2-cell embryos were cut by laser microbeam, cell death occurred 24 h earlier, suggesting important functions of the uncut blastomere in delaying cell death of the cut blastomere. Taken together, we conclude that microbeam-induced DNA damage in early embryos causes compromised development, and that embryos may have their own mechanisms to exclude DNA-damaged blastomeres from participating in further development.

The toxic effects of mobile phone radiofrequency (940 MHz) on the structure of calf thymus DNA

Currently, the biological effects of nonionizing electromagnetic fields (EMFs) including radiofrequency (RF) radiation have been the subject of numerous experimental and theoretical studies. The aim of this study is to evaluate the possible biological effects of mobile phone RF (940 MHz, 15 V/m and SAR=40 mW/kg) on the structure of calf thymus DNA (ct DNA) immediately after exposure and 2 h after 45 min exposure via diverse range of spectroscopic instruments. The UV-vis and circular dichroism (CD) experiments depict that mobile phone EMFs can remarkably cause disturbance on ct DNA structure. In addition, the DNA samples, immediately after exposure and 2 h after 45 min exposure, are relatively thermally unstable compared to the DNA solution, which was placed in a small shielded box (unexposed ct DNA). Furthermore, the exposed DNA samples (the DNA samples that were exposed to 940 MHz EMF) have more fluorescence emission when compared with the unexposed DNA, which may have occurred attributable to expansion of the exposed DNA structure. The results of dynamic light scattering (DLS) and zeta potential experiments demonstrate that RF-EMFs lead to increment in the surface charge and size of DNA. The structure of DNA immediately after exposure is not significantly different from the DNA sample 2 h after 45 min exposure. In other words, the EMF-induced conformational changes are irreversible. Collectively, our results reveal that 940 MHz can alter the structure of DNA. The displacement of electrons in DNA by EMFs may lead to conformational changes of DNA and DNA disaggregation. Results from this study could have an important implication on the health effects of RF-EMFs exposure. In addition, this finding could proffer a novel strategy for the development of next generation of mobile phone.

Effect of electromagnetic field exposure on the reproductive system

The safety of human exposure to an ever-increasing number and diversity of electromagnetic field (EMF) sources both at work and at home has become a public health issue. To date, many in vivo and in vitro studies have revealed that EMF exposure can alter cellular homeostasis, endocrine function, reproductive function, and fetal development in animal systems. Reproductive parameters reported to be altered by EMF exposure include male germ cell death, the estrous cycle, reproductive endocrine hormones, reproductive organ weights, sperm motility, early embryonic development, and pregnancy success. At the cellular level, an increase in free radicals and [Ca²⁺]i may mediate the effect of EMFs and lead to cell growth inhibition, protein misfolding, and DNA breaks. The effect of EMF exposure on reproductive function differs according to frequency and wave, strength (energy), and duration of exposure. In the present review, the effects of EMFs on reproductive function are summarized according to the types of EMF, wave type, strength, and duration of exposure at cellular and organism levels.