Effects of low-frequency magnetic fields on implantation in rats

Electromagnetic field exposure alters in vitro estrogen biosynthesis and its release by the porcine endometrium in the peri-implantation period

The electromagnetic field (EMF) is an environmental risk factor that may impair living organisms. This study aims to determine the functional effects of EMF exposure at 50 and 120 Hz for 2 or 4 h on estrogen synthesis and release in the endometrium. Endometrial slices were isolated from pigs (n = 5) during the peri-implantation period. To check whether progesterone (P₄) exerts any protective effects against EMF, selected EMF-treated slices were also treated with P₄. CYP19A3 mRNA transcript abundance was higher in slices exposed to EMF (50 Hz, 4 h) and treated with P₄. HSD17B4 mRNA transcript abundance was higher in slices exposed to EMF (50 and 120 Hz, 2 h) without P₄ treatment. Both EMF (50 Hz, 2 h) and EMF (50 and 120 Hz, 4 h) increased HSD17B4 mRNA transcript abundance in the presence of P₄; EMF (120 Hz, 2 h, and 50 Hz, 4 h) decreased cytochrome P-450arom protein abundance in tissue slices not treated with P₄. Under exposure to EMF at 120 Hz (2 h), the abundance of hydroxysteroid 17β dehydrogenase decreased in P₄-treated slices and increased in slices not treated with P₄ (4 h). Progesterone treatment decreased the release of estradiol-17β (E₂) in endometrial slices exposed to EMF at 50 Hz (2 h), whereas in slices not treated with P₄, EMF (120 Hz, 2 h) increased estrone (E₁) release compared to control (without EMF). The EMF could disrupt the synthesis and release of E₁ and E₂ by the porcine endometrium during the peri-implantation period.

The effects of a 50-Hz magnetic field on the cardiovascular system in rats

A 50-Hz magnetic field (MF) is a potential health-risk factor. Its effects on the cardiovascular system have not been fully investigated. This study was conducted to explore the effects of long-term exposure to a 50-Hz MF on the cardiovascular system. In the study, an exposure system was constructed, and the distribution of the 50-Hz MF was determined. Sixty-four Sprague-Dawley (SD) rats were exposed to a 50-Hz MF at 100 μT for 24 weeks, 20 h per day, while another 64 rats were sham exposed. During the exposure, blood pressure was measured every 4 weeks. After 24 weeks, echocardiography, cardiac catheterization and electrocardiography were performed. Moreover, heart and body weight were recorded, and haematoxylin-eosin staining and real-time PCR were conducted. The results showed that compared with the sham group, exposure to a 50-Hz MF did not exert any effects on blood pressure, pulse rate, heart rate or cardiac rhythm. Furthermore, echocardiography and cardiac catheterization showed that there were no significant differences in the cardiac morphology or haemodynamics. In addition, histopathological examination showed that exposure to a 50-Hz MF had no effects on the structure of the heart. Finally, expression of the cardiac hypertrophy-related genes did not show any significant differences between the 50-Hz MF exposure group and the sham group. Taken together, in SD rats, exposure to a 50-Hz/100 μT MF for 24 weeks did not show any obvious effects on the cardiovascular system.

Differential effects of high and low strength magnetic fields on mouse embryonic development and vasculogenesis of embryonic stem cells

Man-made magnetic fields (MFs) may exert adverse effects on mammalian embryonic development. Herein, we analysed the effect of 10mT 50Hz sinusoidal (AC) or static (DC) MFs versus 1mT MFs on embryonic development of mice. Exposure for 20days during gestation to 10mT MFs increased resorptions and dead fetuses, decreased crown-rump length and fresh weight, reduced blood vessel differentiation and caused histological changes, accompanied with diminished vascular endothelial growth factor (VEGF) protein expression in several organs. In embryonic stem (ES) cell-derived embryoid bodies exposure towards 10mT MFs increased reactive oxygen species (ROS), decreased vascular marker as well as VEGF expression and enhanced apoptosis. In conclusion, our combined data from in vivo and in vitro experiments identified VEGF as an important mediator during embryonic development that can be influenced by high strength MFs, which in consequence leads to severe abnormalities in fetus organs and blood vessel formation.

Effects of extremely low frequency electromagnetic fields (100μT) on behaviors in rats

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Prolonged exposure to ELF-EMF has no effect on the behavior of the adult male rats.

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Including anxiety/depression like behavior, and spatial/fear learning and memory.

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Exposure to ELF-EMF might be safe.

Recently, extremely low frequency electromagnetic fields (ELF-EMF) have received considerable attentions for their potential pathogenicity. In the present study, we explored the effects of ELF-EMF on behaviors of adult male rats. Sixty adult male rats were randomly divided into two groups, the sham exposure group and the 50 Hz/100 μT ELF-EMF exposure group. During the 24 weeks exposure, body weight, as well as food and water intake were recorded. Results showed that food and water intake and the body weight of the rats were not affected by the exposure. After 24 weeks exposure, open field test and elevated plus maze were conducted to evaluate the anxiety-like behavior, the tail suspension test and forced swim test were conducted to evaluate depression-like behavior and Morris water maze and fear conditioning tests were used to evaluate the cognitive and memory ability. Exposure to ELF-EMF did not induce any anxiety-like or depression-like behaviors compared with the sham exposure. Moreover, the cognitive and memory ability was not impaired by the ELF-EMF exposure. Furthermore, ELF-EMF exposure did not affect the morphology and histology of the brain. In conclusion, 24 weeks exposure to 50 Hz/100 μT ELF-EMF had no effect on the behaviors of the adult male rats.

Use of mobile phone during pregnancy and the risk of spontaneous abortion

BACKGROUND

Exposure to electromagnetic fields of cell phones increasingly occurs, but the potential influence on spontaneous abortion has not been thoroughly investigated.

METHODS

In a case-control study, 292 women who had an unexplained spontaneous abortion at < 14 weeks gestation and 308 pregnant women > 14 weeks gestation were enrolled. Two data collection forms were completed; one was used to collect data about socioeconomic and obstetric characteristics, medical and reproductive history, and lifestyles. Another was used to collect data about the use of cell phones during pregnancy. For the consideration of cell phone effects, we measured the average calling time per day, the location of the cell phones when not in use, use of hands-free equipment, use of phones for other applications, the specific absorption rate (SAR) reported by the manufacturer and the average of the effective SAR (average duration of calling time per day × SAR). Analyses were carried out with statistical package state software(SPSS)v.16.

RESULTS

All the data pertaining to mobile phones were different between the two groups except the use of hands free devices (p < 0.001).

CONCLUSION

Our result suggests that use of mobile phones can be related to the early spontaneous abortions.

The effects of pulsed electromagnetic field on the functions of osteoblasts on implant surfaces with different topographies

The use of pulsed electromagnetic fields (PEMFs) is a promising approach to promote osteogenesis. However, few studies have reported the effects of this technique on the osseointegration of endosseous implants, especially with regard to different implant topographies. We focused on how the initial interaction between cells and the titanium surface is enhanced by a PEMF and the possible regulatory mechanisms in this study. Rat osteoblasts were cultured on three types of titanium surfaces (Flat, Micro and Nano) under PEMF stimulation or control conditions. Protein adsorption was significantly increased by the PEMF. The number of osteoblasts attached to the surfaces in the PEMF group was substantially greater than that in the control group after 1.5h incubation. PEMF stimulation oriented the osteoblasts perpendicular to the electromagnetic field lines and increased the number of microfilaments and pseudopodia formed by the osteoblasts. The cell proliferation on the implant surfaces was significantly promoted by the PEMF. Significantly increased extracellular matrix mineralization nodules were observed under PEMF stimulation. The expression of osteogenesis-related genes, including BMP-2, OCN, Col-1,ALP, Runx2 and OSX, were up-regulated on all the surfaces by PEMF stimulation. Our findings suggest that PEMFs enhance the osteoblast compatibility on titanium surfaces but to different extents with regard to implant surface topographies. The use of PEMFs might be a potential adjuvant treatment for improving the osseointegration process.

The effects of extremely low-frequency magnetic fields on melatonin and cortisol, two marker rhythms of the circadian system

In the past 30 years the concern that daily exposure to extremely low-frequency magnetic fields (ELF-EMF) (1 to 300 Hz) might be harmful to human health (cancer, neurobehavioral disturbances, etc) has been the object of debate, and has become a public health concern. This has resulted in the classification of ELF-EMF into category 2B, ie, agents that are “possibly carcinogenic to humans” by the International Agency for Research on Cancer. Since melatonin, a neurohormone secreted by the pineal gland, has been shown to possess oncostatic properties, a “melatonin hypothesis” has been raised, stating that exposure to EMF might decrease melatonin production and therefore might promote the development of breast cancer in humans. Data from the literature reviewed here are contradictory. In addition, we have demonstrated a lack of effect of ELF-EMF on melatonin secretion in humans exposed to EMF (up to 20 years' exposure) which rebuts the melatonin hypothesis. Currently, the debate concerns the effects of ELF-EMF on the risk of childhood leukemia in children chronically exposed to more than 0.4 μT. Further research is thus needed to obtain more definite answers regarding the potential deleterious effects of ELF-EMF.

Low frequency vibrations disrupt left-right patterning in the Xenopus embryo

The development of consistent left-right (LR) asymmetry across phyla is a fascinating question in biology. While many pharmacological and molecular approaches have been used to explore molecular mechanisms, it has proven difficult to exert precise temporal control over functional perturbations. Here, we took advantage of acoustical vibration to disrupt LR patterning in Xenopus embryos during tightly-circumscribed periods of development. Exposure to several low frequencies induced specific randomization of three internal organs (heterotaxia). Investigating one frequency (7 Hz), we found two discrete periods of sensitivity to vibration; during the first period, vibration affected the same LR pathway as nocodazole, while during the second period, vibration affected the integrity of the epithelial barrier; both are required for normal LR patterning. Our results indicate that low frequency vibrations disrupt two steps in the early LR pathway: the orientation of the LR axis with the other two axes, and the amplification/restriction of downstream LR signals to asymmetric organs.

Evaluation of hormonal change, biochemical parameters, and histopathological status of uterus in rats exposed to 50-Hz electromagnetic field

This study investigates the effects of the electromagnetic field (EMF) resulting from the 170 kV high-voltage power lines on hormonal status, on progesterone and 17-beta estradiol levels, and on morphology of the uterus and ovaries associated with biochemical parameters of adult Wistar female rats. The rats were assigned to experimental (21) and control groups (7). The rats in the experimental group were housed in a wooden barn with 7.5 m vertical distance to the power line. Groups 1, 2, and 3 were exposed continuously (24 h) to electric-electromagnetic fields (ELF-EMFs) (48.21 +/- 1.58 mG) for 1, 2, and 3 months, respectively. The rats of group 4 served as the control and were placed in laboratory conditions (The average value of the ELF was 0.75 +/- 0.05 V/m. The value of the EMF was calculated to be 0.48 +/- 0.05 mG.). Significant (P < 0.05) decreases were determined among the groups in terms of reproductive organ weights (uterus and ovaries) and progesterone and estrogen levels in relation to the varying periods of the estrous cycle. Although marked reductions (P < 0.05) were observed among the groups in relation to plasma catalase activity, depending on exposure time, no significant differences were found in terms of glutathione and malondialdehyde levels. It is concluded that exposure to the ELF-EMFs for different time periods produced significant decreases in plasma catalase activities in the 3-month exposure groups but no effects on progesterone level, on 17-beta estradiol level, or on the morphology and weight of uterus and ovaries.

Effects of exposure to 50Hz magnetic field of 1mT on the performance of detour learning task by chicks

In the present study, we examined the effects of exposure to an extremely low-frequency magnetic field of 1 mT intensity on learning and memory in Lohmann brown domestic chicks using detour learning task. These results show that 20 h/day exposure to a low-frequency magnetic field induces a significant impairment in detour learning but 50 min/day exposure has no effect.

Effects of 50 Hz extremely low frequency magnetic field on the morphology and function of boar spermatozoa capacitated in vitro

The aim of this study was to evaluate the effect of an acute exposure to a sinusoidal MF-ELF (50 Hz, 1mT) on the ability of boar mature spermatozoa to acquire the fertilizing competence in vitro. The spermatozoa exposed during the 4h of incubation to the MF-ELF were evaluated for morphological (surface morphology and acrosome integrity) and functional parameters (cell viability, motility, induction of acrosomal reaction, AR, and the ability to in vitro fertilize oocytes). In parallel, the intracellular Ca(2+) levels as well as the major mechanisms of Ca(2+) clearance were assessed: (45)Ca intakes and intracellular Ca(2+) sequestration by analyzing intracellular Ca(2+) elevation induced by thapsigargin or studying mitochondrial function with Mito-Tracker. The MF-ELF exposure did not affect sperm viability and morphology during the first h of incubation when sperm Ca(2+) homeostasis were already compromised. First of all, MF-ELF treated spermatozoa showed resting intracellular Ca(2+) levels significantly lower than those recorded in controls. This result was dependent on a lower extracellular Ca(2+) intake and from the inhibitory role exerted on both intracellular Ca(2+) storages. As a consequence, after 1h of incubation MF-ELF exposed cells displayed a reduced motility, a modest reactivity when coincubated with solubilized zonae pellucidae and a reduction in oocyte penetrating ability. After 2 or 4h of incubation, in addition, signs of morphological damage appeared on plasma membrane and at acrosomal level. In conclusion, MF-ELF influence negatively spermatozoa first by impairing cell Ca(2+) homeostasis then by dramatically affecting sperm morphology and function.

Mouse early embryos obtained by natural breeding or in vitro fertilization display a differential sensitivity to extremely low-frequency electromagnetic fields

We have investigated the sensitivity of pre-implantation embryos obtained by natural breeding (NB) or in vitro fertilization (IVF) to extremely low-frequency magnetic fields (ELF-MF). Fertilized eggs obtained by NB were removed from mothers 12h after mating and cultured in vitro for 5 days under continuous ELF-MF exposure (constant strength of 50Hz and various intensities, i.e. 60, 120 and 220 microT). Alternatively, zygotes obtained by IVF were subjected to ELF-MF exposure (50Hz, 60 microT), starting 12h after IVF for 5 days. We found that ELF-MF exposure causes a small yet significant (P<0.05) decrease in the survival rate of NB-derived embryos at the latest stages of pre-implantation development, i.e. the eight cell-to-blastocyst transition. In embryos exposed to the highest field intensity (220 microT), the effect became apparent somewhat earlier. When IVF-derived embryos were exposed to ELF-MF, the reduction in the rate of embryo survival was more pronounced and the difference from controls was more significant (P<0.01). Moreover, the decreased survival rate in IVF embryos became apparent as early as the first cleavage and persisted throughout pre-implantation. These results suggest that IVF-derived embryos are more sensitive than NB-generated embryos to ELF-MF, and that this sensitivity occurs earlier in development.