Long-term (up to 20years) effects of 50-Hz magnetic field exposure on blood chemistry parameters in healthy men

Extremely low frequency electromagnetic fields exposure during the prenatal and postnatal periods alters pro-inflammatory cytokines levels by gender

Maternal exposure to the excessive electromagnetic fields is considered harmful to infants and associated with several health problems in life, such as neurological or immune diseases. In this present study we aimed to investigate the potential effects of extremely low-frequency electromagnetic field (ELF-EMF) exposure during the gestational and lactational period of dams on immune system parameters. The development of white blood cells (WBC), lymphocyte subpopulations (CD4⁺ T cells, CD8⁺ T cells, Natural Killer (NK) cells, and B cells) and production of T cell related cytokines were explored in the offsprings. Significant changes were found in WBC and lymphocyte counts. Although no changes in lymphocyte subunits were observed among groups, CD4⁺ cells were significantly increased in the female group exposed to ELF-EMF. Also, IL-17A and IFN-γ levels increased in plasma and spleen. The mean IL-4 level and the expression level of the IL-4 gene were not changed, in the experimental groups. But the expression of the IL-17A gene was also upregulated, which supports cytokine quantification analyses. In conclusion, ELF-EMF exposure in the prenatal and postnatal period increases the level of IL-17A in the spleen and blood of young female rats, and it upregulates IL-17 gene expression in the spleen, resulting in CD4⁺ cell proliferation and inflammation.

An Investigation Into the Effects of Long-Term 50-Hz Power-Frequency Electromagnetic Field Exposure on Hematogram, Blood Chemistry, Fibrosis, and Oxidant Stress Status in the Liver and the Kidney From Sprague-Dawley Rats

Power-frequency electromagnetic fields (PF-EMFs) at 50 Hz are potential health risk factors. This study aimed to explore the effects of long-term exposure to 50-Hz PF-EMFs on general physiological conditions in Sprague-Dawley (SD) rats. During a 24-week exposure period, the body mass and water and food intake of the animals were recorded regularly. The hematologic parameters were detected every 12 weeks, and blood chemistry analyses were performed every 4 weeks. After sacrifice, morphology was identified by hematoxylin-eosin, Masson, and immunohistochemical staining. Fibrosis-related gene expression and oxidative stress status were also detected. Compared with the control group, exposure to 30, 100, or 500 μT PF-EMF did not exert any effect on body mass, food intake, or water intake. Similarly, no significant differences were found in hematologic parameters or blood chemistry analyses among these groups. Furthermore, morphological assays showed that exposure to PF-EMFs had no influence on the structure of the liver or kidney. Finally, fibrosis-related gene expression and oxidative stress status were unaltered by PF-EMF exposure. The present study indicates that 24 weeks of exposure to PF-EMFs at intensities of 30, 100, or 500 μT might not affect hemograms, blood chemistry, fibrosis, or oxidative stress in the liver or kidney in SD rats. © 2020 Bioelectromagnetics Society.

Evaluation in humans of ELF-EMF exposure on chromogranin A, a marker of neuroendocrine tumors and stress

Chromogranin A (CgA), which is a major protein in adrenal chromaffin cells and adrenergic neurons, is a clinically relevant endocrine and neuroendocrine tumor marker including pheochromocytomas, neuroblastomas, and related neurogenic tumors. In this study, we looked at the effect in humans of chronic daily exposure to a 50-Hz magnetic field. We examined in 15 men (38.0 ± 0.9 years) the effects of chronic daily exposure to a 50-Hz magnetic field for 1-20 yrs both at home and at work. EMDEX II dosimeters were used to record magnetic field all day long every 30 s. for 1 week. The weekly geometric mean of the individual exposures ranged from 0.1 to 2.6 μT. Blood samples were taken hourly between 20:00 h and 08:00 h. CgA patterns of exposed subjects were compared to age-matched controls. The results of exposed subjects were compared with those for 15 unexposed men who served as controls and whose individual exposure was ten times lower ranging from 0.004 to 0.092 μT. This work shows that in the control group the serum CgA levels exhibited a nighttime peak with a progressive decline of the serum concentrations and a nadir in the morning. Both the profile and the serum concentrations of CgA, a marker of neuroendocrine tumors and stress, did not appear to be impaired in the subjects chronically exposed over a long period (up to 20 yrs) to magnetic fields though a trend toward lower levels were found at the highest exposure (>0.3 μT). This does not rule out, however, that the potential deleterious risk of ELF-EMF on frail populations such as children and the elderly may be greater at low exposure and should hence be documented, at least for their residential exposure.

DNA effects of low level occupational exposure to extremely low frequency electromagnetic fields (50/60 Hz)

AIMS

Exposure to extremely low frequency magnetic fields (ELF-MF) occurs from natural and artificial sources. Although ELF-MF has been classified as a suspected humans carcinogen agent by the International Agency for Research on Cancer, little is known of the effects of ELF-MF at lower exposure levels of the recommended range. In the present study, DNA damage in the peripheral blood cells of power line workers was investigated.

MATERIALS AND METHODS

Occupational exposure to ELF-MF in a power plant was measured using the National Institute for Occupational Safety and Health (NIOSH) manual. Single-strand breaks (SSBs) in DNA were evaluated in 29 male utility workers as the exposed population and 28 male support personnel as the control subjects using the comet assay. Effects of ELF-MF on subjects were evaluated using DNA percent in tails, tail length, olive length, and tail moment.

RESULTS

Occupational exposure levels to ELF-MF in the utility workers were less than the threshold limit values (TLV) recommended by the American Conference of Government Industrial Hygienist (ACGIH). The median value of the magnetic field at the working sites was 0.85 µT. Induction of DNA damage was observed for the exposed workers compared with the controls. Olive length, tail moment, and tail DNA percent increased significantly (p < 0.05) in the utility workers.

CONCLUSIONS

Exposure to ELF-MF at levels less than the ACGIH exposure limit can produce DNA strand breaks.

Reactive oxygen species mediates 50-Hz magnetic field-induced EGF receptor clustering via acid sphingomyelinase activation

PURPOSE

Exposure to extremely low frequency electromagnetic fields (ELF-EMFs) could elicit biological effects including carcinogenesis. However, the detailed mechanisms by which these ELF-EMFs interact with biological system are currently unclear. Previously, we found that a 50-Hz magnetic field (MF) exposure could induce epidermal growth factor receptor (EGFR) clustering and phosphorylation on cell membranes. In the present experiment, the possible roles of reactive oxygen species (ROS) in MF-induced EGFR clustering were investigated.

MATERIALS AND METHODS

Human amnion epithelial (FL) cells were exposed to a 50-Hz MF with or without N-acetyl-l-cysteine (NAC) or pyrrolidine dithiocarbamate (PDTC). EGFR clustering on cellular membrane surface was analyzed using confocal microscopy after indirect immunofluorescence staining. The intracellular ROS level and acid sphingomyelinase (ASMase) activity were detected using an ROS assay kit and an Amplex^® Red Sphingomyelinase Assay Kit, respectively.

RESULTS

Results showed that exposure of FL cells to a 50-Hz MF at 0.4 mT for 15 min significantly enhanced the ROS level, induced EGFR clustering and increased ASMase activity. However, pretreatment with NAC or PDTC, the scavenger of ROS, not only counteracted the effects of a 50-Hz MF on ROS level and AMS activity, but also inhibited the EGFR clustering induced by MF exposure.

CONCLUSIONS

The present and previous data suggest that ROS mediates the MF-induced EGFR clustering via ASMase activation.

Effects of Intermittent and Continuous Magnetic Fields on Trace Element Levels in Guinea Pigs

Electromagnetic fields (EMFs) can affect living cells due to biochemical changes, followed by changes in levels of trace elements in serum and different organs. This study focuses on the effect of whole body exposure to EMF, presented everywhere in our environment, and on the levels of trace elements in serum, femur, brain, kidney, and liver tissues. The analyses performed on 29 guinea pigs were divided into five groups. Guinea pigs were exposed to a magnetic field of 50 Hz of 1.5 mT. Groups A and B were exposed to the magnetic field for a period of 4 h/day continuously (4 h/day) for 4 and 7 days, respectively. Groups C and D were exposed to the magnetic field for a period of 4 h/day intermittently for 4 and 7 days, respectively. Group E animals were enrolled as control. Copper (Cu), zinc (Zn), calcium (Ca), and magnesium (Mg) levels were determined by atomic absorption spectroscopy in serum, femur, brain, kidney, and liver tissues in all guinea pigs. When compared to the control groups, the changes in the levels of Cu in serum samples, femur, and kidney tissues of the treated groups were statistically significant. The same was also true for the levels of Mg in the brain, kidney, and lung tissues. Our results suggest that in vivo continuous and intermittent exposure to EMF may cause disturbances in homeostasis of bioelements. These effects could be important risk factors for toxic effects of EMF, especially in relation to deterioration of bioelements.

Effects of static magnetic field exposure on plasma element levels in rat

The interaction of static magnetic fields (SMFs) with living organisms is a rapidly growing field of investigation. The magnetic fields (MFs) effect observed with radical pair recombination is one of the well-known mechanisms by which MFs interact with biological systems. SMF influenced cellular antioxidant defense mechanisms by affecting antioxidant enzymes such as superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT). However, there were insufficient reports about the effects of SMF on macro and trace elements in serum, and the results were contradictory until now. In the current study, 12 rats were divided into two groups, namely as control and exposure group (128 mT and 1 h/day during five consecutive days). The macro and trace element concentrations in serum were examined. No significant difference was observed in the sodium (Na), potassium (K), calcium (Ca), phosphorus (P), and selenium (Se) levels in rat compared to control. By contrast, exposure to SMF showed an increase in the zinc (Zn) level and a decrease in iron (Fe) concentration. Under our experimental conditions, SMF exposure cannot affect the plasma levels of macroelements, while it can disrupt Zn and Fe concentrations in rat.