Extremely low frequency magnetic field (50 Hz, 0.5 mT) modifies fitness components and locomotor activity of Drosophila subobscura

Abstract

Purpose: Extremely low frequency (ELF) magnetic fields are essential ecological factors which may induce changes in many organisms. The aim of this study was to examine the effects in Drosophila subobscura exposed for 48 h to ELF magnetic field (50 Hz, 0.5 mT) at different developmental stages.

Materials and methods: Egg-first instar larvae developmental stage of D. subobscura isofemale lines was exposed to ELF magnetic field, and fitness components (developmental time, developmental dynamics, viability and sex ratio) and locomotor activity of three-day-old males and females were monitored. Also, just eclosed D. subobscura isofemale adults were exposed to ELF magnetic field and their locomotor activity was monitored just after.

Results: ELF magnetic field shortens developmental time, increases viability and does not affect sex ratio of D. subobscura. No matter which developmental stage is exposed, ELF magnetic field significantly decreases locomotor activity of adult flies, but after exposure of just eclosed adults observed change lasts longer.

Conclusions: Applied ELF magnetic field modifies fitness components and locomotor activity of D. subobscura. Observed effects can be attributed to the influence of magnetic field on different stages of development where the hormonal and nervous systems play important role in the control of examined parameters.     

Assessment of genetic damage in peripheral blood of human volunteers exposed (whole-body) to a 200 μT, 60 Hz magnetic field

Aim:?To investigate the extent of damage in nucleated cells in peripheral blood of healthy human volunteers exposed to a whole-body 60 Hz, 200 μT magnetic field.

Materials and methods:?In this study, 10 male and 10 female healthy human volunteers received a 4 h whole-body exposure to a 200 μT, 60 Hz magnetic field. In addition, five males and five females were treated in a similar fashion, but were exposed to sham conditions. For each subject, a blood sample was obtained prior to the exposure period and aliquots were used as negative- (pre-exposure) and positive- [1.5 Gray (Gy) ⁶⁰Cobalt (⁶⁰Co) γ-irradiation] controls. At the end of the 4 h exposure period, a second blood sample was obtained. The extent of DNA damage was assessed in peripheral human blood leukocytes from all samples using the alkaline comet assay. To detect possible clastogenic effects, the incidence of micronuclei was assessed in phytohemagglutinin (PHA)-stimulated lymphocytes using the cytokinesis-block micronucleus assay.

Results:?There was no evidence of either increased DNA damage, as indicated by the alkaline comet assay, or increased incidence of micronuclei (MN) in the magnetic field exposed group. However, an in vitro exposure of 1.5 Gy γ-irradiation caused a significant increase in both DNA damage and MN induction.

Conclusions: This study found no evidence that an acute, whole-body exposure to a 200 μT, 60 Hz magnetic field for 4 hours could cause DNA damage in human blood.     

Clastogenicity and aneuploidy in newborn and adult mice exposed to 50 Hz magnetic fields

Purpose:?To detect possible clastogenic and aneugenic properties of a 50 Hz, 650 μT magnetic field.

Materials and methods:?The micronucleus test with CREST (Calcinosis, Raynaud's phenomenon, Esophageal dismotility, Sclerodactility, Telangectasia) antibody staining was performed on liver and peripheral blood sampled from newborn mice exposed to an ELF (Extremely Low Frequency) magnetic field during the whole intra-uterine life (21 days), and on bone marrow and peripheral blood sampled from adult mice exposed to the same magnetic field for the same period.

Results:?Data obtained in newborn mice show a significant increase in micronuclei frequencies. In absolute terms, most of the induced micronuclei were CREST-negative (i.e., formed by a chromosome fragment). However, in relative terms, ELF exposure caused a two-fold increase in CREST-negative micronuclei and a four-fold increase in CREST-positive micronuclei (i.e., formed by a whole chromosome). No significant effect was recorded on exposed adults.

Conclusions:?These findings suggest the need for investigation of aneugenic properties of ELF magnetic fields in order to establish a possible relationship to carcinogenesis.     

The influence of static magnetic field (50 mT) on development and motor behaviour of Tenebrio (Insecta,Coleoptera)

Abstract

Purpose: There is considerable concern about potential effects associated with exposure to magnetic fields on organisms. Therefore, duration of pupa-adult development and motor behaviour of adults were analyzed in Tenebrio obscursus and T. molitor after exposure to static magnetic field (50 mT).

Material and methods: The experimental groups were: Control (kept 5 m from the magnets), groups which pupae and adults were placed closer to the North pole, or closer to the South pole of magnetic dipole. The pupae were exposed to the magnetic field until the moment of adult eclosion. The pupa-adult development dynamics were recorded daily. Subsequently, behaviour (distance travelled, average speed and immobility) of adults exposed to the magnetic field was monitored in a circular open field arena.

Results: Static magnetic field did not affect pupa-adult developmental dynamic of examined Tenebrio species. Exposure to magnetic field did not significantly change motor behaviour of T. obscurus adults. The changes in the motor behaviour of T. molitor induced by static magnetic field were opposite in two experimental groups developed closer to the North pole or closer to the South pole of magnetic dipole.

Conclusion: Static magnetic field (50 mT) did not affect on pupa-adult development dynamic of two examined Tenebrio species, but modulated their motor behaviour.     

Pre-exposure to 50 Hz magnetic fields modifies menadione-induced DNA damage response in murine L929 cells

Purpose: Effects on DNA damage response were investigated in murine L929 cells exposed to 50 Hz magnetic fields (MF) with or without ultraviolet B (UVB, wavelength 280–320 nm) radiation or menadione (MQ).

Materials and methods: Cells were exposed to MF at 100 or 300 μT combined with MQ (150 μM, 1 hour) or UVB radiation (160 J/m²) using various exposure schedules. The samples were stained with propidium iodide (PI) and analysed by flow cytometer for cell cycle stages. Apoptotic cells were defined as sub G₁ events.

Results: In cells first exposed to 100 μT MF for 24 h, the response to subsequent MQ treatment was significantly altered so that the proportion of sub G₁ cells was decreased and the proportion of cells in the G₂/M phase was increased. When a 300 μT MF was used, also the proportion of cells in the G₁ phase was decreased. MF exposures after MQ treatment did not alter responses to MQ. No effects were found from MF exposure alone or from MF combined with UVB radiation.

Conclusions: The results strengthen previous findings suggesting that pre-exposure to MF can alter cellular responses to other agents, and indicate that MF as low as 100 μT has measurable impacts on cancer-relevant cellular processes such as DNA-damage.     

Evaluation of cell viability,DNA single-strand breaks,and nitric oxide production in LPS-stimulated macrophage RAW264 exposed to a 50-Hz magnetic field

Purpose: Synergistic effects between cellular oxidative stress and magnetic fields may explain the adverse biological effects of 50/60?Hz magnetic fields. To determine whether this hypothesis holds in macrophage RAW264 cells, we measured DNA single-strand breaks (SSB), cell viability, and nitric oxide (NO) production in cells with or without exposure to 0.5-mT, 50-Hz magnetic fields for 24?h and with or without simultaneous stimulation via the bacterial endotoxin, lipopolysaccharide (LPS).

Materials and methods: Macrophages stimulated with 10?ng/ml LPS for 1?h were exposed to or not exposed to a magnetic field and were then subjected to (1) the alkaline comet assay to measure SSBs, (2) trypan-blue exclusion assay for cell viability, and (3) measurements of NO for evaluation of oxidative stress.

Results: The 50-Hz magnetic field enhanced DNA SSB and decreased cell viability only in the LPS-stimulated macrophages in which NO production was greatly enhanced. The magnetic field alone did not alter NO production.

Conclusion: Co-stimulation of the cell with LPS and a 50-Hz magnetic field promoted SSB and lowered cell viability, but these were not mediated by LPS-induced NO production.     

Magnetic field (50 Hz) increases N‐acetyltransferase,hydroxy‐indole‐O‐methyltransferase activity and melatonin release through an indirect pathway

Purpose: To examine whether magnetic fields (MF) affect N‐acetyltransferase (NAT) and hydroxy‐indole‐O‐methyltransferase (HIOMT) activity directly or exert their effect through a cellular pathway that indirectly regulates the activity of these enzymes and melatonin release.

Materials and methods: The pineal glands from Wistar rats were isolated at 10:00?h and exposed to MF (50?Hz, 1?mT) for 4?h in vitro, with or without 1?µM norepinephrine. An additional group of pineals was exposed to MF 30?min before norepinephrine addition. The direct effect of MF on the activity of the enzymes was studied in sonicated glands exposed to MF. NAT activity, HIOMT activity and melatonin release were determined.

Results: In pineal glands isolated in the morning, 4‐h in vitro exposure did not affect the basal release of melatonin from the pineal gland as well as the basal NAT and HIOMT activities. Pineal gland exposure to MF 30?min before norepinephrine addition significantly (p<0.05) increased NAT activity, HIOMT activity and melatonin release (p<0.05). These effects were not observed in pineals co‐treated with MF and norepinephrine or in sonicated glands exposed to MF.

Conclusions: The results suggest that in pineals isolated in the morning, 4‐h MF exposure changes melatonin release by affecting the signal transduction pathway leading from the norepinephrine receptor to NAT and HIOMT and not via a direct effect at the enzyme levels.     

Long-term exposure of cockroach Blaptica dubia (Insecta: Blaberidae) nymphs to magnetic fields of different characteristics: effects on antioxidant biomarkers and nymphal gut mass

Abstract

Purpose: The main goal of this study was to analyze the long-term effects of static (SMF) and extremely low-frequency magnetic field (ELF MF) on nymphal gut mass and antioxidant biomarkers in this tissue of cockroach Blaptica dubia.

Materials and methods: One-month-old nymphs were exposed to magnetic field (MF) for 5 months in three experimental groups: control, exposure to SMF (110?mT) and exposure to ELF MF (50?Hz, 10?mT).

Results: The gut masses of the MF groups were significantly lower when compared to control. Superoxide dismutase (SOD) and catalase (CAT) activities were markedly higher than for the control and the differences between the MF groups were statistically significant only for SOD. The applied MF had no effect on total glutathione (GSH) content. Glutathione reductase (GR) and glutathione S-transferase (GST) activities were significantly lower in both MF groups in comparison to the control. There was a significant difference between MF groups for GR activity. Principal Component Analysis (PCA) showed that CAT and GST were the main factors contributing to the differentiation of the control group from the treated experimental groups along PCA 1, and SOD and GR along PCA 2. PCA revealed clear separation between experimental groups depends on antioxidant biomarker response.

Conclusion: The applied magnetic fields could be considered a potential stressor influencing gut mass, as well as examined antioxidative biomarkers.     

Radiofrequency radiation does not significantly affect ornithine decarboxylase activity,proliferation, or caspase-3 activity of fibroblasts in different physiological conditions

Purpose: The aim of this study was to test the hypothesis that variations in the physiological state of cells explain inconsistent results from in vitro studies on biological effects of radiofrequency (RF) radiation.

Materials and methods: Murine L929 fibroblasts stimulated with fresh medium, stressed with serum deprivation or not subjected to stimulation or stress were exposed in a waveguide exposure chamber to 872 MHz continuous wave or pulse modulated (217 pulses per second) RF radiation at specific absorption rate of 5 W/kg. Ornithine decarboxylase (ODC) activity after 1-and 24-h exposures, proliferation during 48 h after 24 h exposure, and caspase-3 activity (a measure of apoptosis) after 1 h exposure were measured.

Results: The cells responded to fresh medium and serum deprivation, but no consistent effects of RF radiation were found. One statistically significant (p = 0.03) RF radiation-related difference was observed in ODC activity, but this is most likely a chance finding, as many statistical comparisons were performed, and the finding was not supported by any other data.

Conclusions: The results did not support effects on the endpoints studied. Furthermore, stressed and stimulated cells were not more sensitive than normal cells to possible RF radiation-induced effects.     

Can safe and long-term exposure to extremely low frequency (50 Hz) magnetic fields affect apoptosis,reproduction, and oxidative stress?

Abstract

Purpose: To determine whether 50 Hz extremely low frequency-magnetic fields (ELF-MF) affects apoptotic processes, oxidative damage, and reproductive characteristics such as sperm count and morphology in rat testes.

Materials and methods: Thirty male Sprague-Dawley rats were used in the present study, which were divided into three groups (sham group, n = 10, and two experimental groups, n = 10 for each group). Rats in the experimental group were exposed to 100 and 500 μT ELF-MF (2 h/day, 7 days/week, for 10 months) corresponding to exposure levels that are considered safe for humans. The same experimental procedures were applied to the sham group, but the ELF generator was turned off. Tissues from the testes were immunohistochemically stained for active (cleaved) caspase-3 in order to measure the apoptotic index by a semi-quantitative scoring system. The levels of catalase (CAT), malondialdehyde (MDA), myeloperoxidase (MPO), total antioxidative capacity (TAC), total oxidant status (TOS), and oxidative stress index (OSI) were also measured. Additionally, epididymal sperm count and sperm morphology was evaluated.

Results: There were no significant differences in the reproductive and oxidative stress parameters between the sham group and the exposed groups (p > 0.05). While no difference was observed between the final apoptosis score of the sham and the 100 μT ELF-MF group (p > 0.05), the final apoptosis score was higher in the 500 μT ELF-MF exposure group than in the sham group (p < 0.05).

Conclusion: Long-term exposure to 100 μT and 500 μT ELF-MF did not affect oxidative or antioxidative processes, lipid peroxidation, or reproductive components such as sperm count and morphology in testes tissue of rats. However, long-term exposure to 500 μT ELF-MF did affect active-caspase-3 activity, which is a well-known apoptotic indicator.     

Growth of injected melanoma cells is suppressed by whole body exposure to specific spatial-temporal configurations of weak intensity magnetic fields

Purpose:?To measure the effect of exposure to a specific spatial-temporal, hysiologically-patterned electromagnetic field presented using different geometric configurations on the growth of experimental tumours in mice.

Methods:?C57b male mice were inoculated subcutaneously with B16-BL6 melanoma cells in two blocks of experiments separated by six months (to control for the effects of geomagnetic field). The mice were exposed to the same time-varying electromagnetic field nightly for 3?h in one of six spatial configurations or two control conditions and tumour growth assessed.

Results:?Mice exposed to the field that was rotated through the three spatial dimensions and through all three planes every 2 sec did not grow tumours after 38 days. However, the mice in the sham-field and reference controls showed massive tumours after 38 days. Tumour growth was also affected by the intensity of the field, with mice exposed to a weak intensity field (1–5 nT) forming smaller tumours than mice exposed to sham or stronger, high intensity (2–5?μT) fields. Immunochemistry of tumours from those mice exposed to the different intensity fields suggested that alterations in leukocyte infiltration or vascularisation could contribute to the differences in tumour growth.

Conclusions:?Exposure to specific spatial-temporal regulated electromagnetic field configurations had potent effects on the growth of experimental tumours in mice.     

Diary of events

Purpose: To discern changes in blood chemistry, cerebral sizes, and hippocampal cytomorphology in adult male and female albino Wistar rats that had been exposed during their entire prenatal development to one of two patterns of magnetic fields and one of four intensities: Very low 5 – 20 nT; low 30 – 50 nT; medium 90 – 580 nT; and high 590 nT to 1.2 microT.

Materials and methods: A total of 48 pregnant females were exposed to either a repetitive frequency-modulated magnetic field or to a complex sequence of 50, 200-msec physiologically-patterned fields. As adults blood, cerebral, and histomorphological data were obtained from the 137 rats that had been exposed to one of these eight conditions.

Results: Compared to other groups, adult rats that had been exposed prenatally to the physiologically-patterned magnetic fields at the low (30 – 50 nT) and medium (90 – 580 nT) intensities exhibited peak elevations of aminotransaminase, glucose, and uric acid. Numbers of cytometric anomalies were also significantly elevated within regions of the hippocampus known for neuronal neogenesis in adults.

Conclusions: The results suggest that a common factor in cellular adhesion or plasticity might be permanently altered by prenatal exposure to a narrow intensity of a series of physiologically-patterned magnetic fields.     

Chronic exposure of Sprague-Dawley rats to 20 kHz triangular magnetic fields

Purpose:?As a continuing study of 20?kHz triangular magnetic fields (MF) [Lee et al. ], we investigated the chronic toxicity and possible health effects of exposure to 20?kHz MF at the flux density of 30?μT, which is the limit standard for the occupational population in South Korea, with the use of Sprague-Dawley rats.

Materials and methods:?Rats were exposed to 20?kHz triangular MF at 30?μT Root Mean Square for 8?h/day for 18 months. Body and organ weights were measured and urinalysis, hematological and blood biochemistry analyses were performed in individual animals. Histopathological evaluation was also performed for the brain, thymus, lung, heart, liver, kidney, intestine and reproductive organs, including tumour tissue.

Results:?The mortality patterns in male or female rats exposed to magnetic fields were compared to the mortality patterns found in sex-matched sham control animals. Significant alteration of body weight was not observed with MF exposure. No significant differences were seen in sham-exposed and MF-exposed animals based on urological factors, hematological factors and blood biochemistry. Total tumour incidence was not different between sham-exposed and MF-exposed animals.

Conclusion:?Our results suggest that chronic exposure to 20?kHz triangular MF with 30?μT flux density did not increase toxicity in rats.     

Superposition of an incoherent magnetic field inhibited EGF receptor clustering and phosphorylation induced by a 1.8 GHz pulse-modulated radiofrequency radiation

Abstract

Purpose: The present study was conducted to investigate the effect of a temporally incoherent (‘noise’) magnetic field (MF) on radiofrequency radiation (RFR)-induced epidermal growth factor (EGF) receptor clustering and phosporylation in cultured cells.

Materials and methods: Human amniotic epithelial (FL) cells were exposed for 15 min to either a 1.8 GHz RFR (modulated at 217 Hz), a 2 μT incoherent MF, or concurrently to the RFR and incoherent MF. Epidermal growth factor treatment severed as the positive control. Epidermal growth factor receptor clustering on cellular membrane surface was analyzed using confocal microscopy after indirect immunofluorescence staining, and phosphorylation of EGF receptors was measured by western blot technology.

Results: Exposure of FL cells to the 1.8 GHz RFR at SAR (specific absorption rate) of 0.5, 1.0, 2.0, or 4.0 W/kg for 15 min induced EGF receptor clustering and enhanced phosphorylation on tyrosine-1173 residue, whereas exposure to RFR at SAR of 0.1 W/kg for 15 min did not significantly cause these effects. Exposure to a 2 μT incoherent MF for 15 min did not significantly affect clustering and phosphorylation of EGF receptor in FL cells. When superimposed, the incoherent MF completely inhibited EGF receptor clustering and phosphorylation induced by RFR at SAR of 0.5, 1.0, and 2.0 W/kg, but did not inhibit the effects induced at SAR of 4.0 W/kg.

Conclusion: Based on the data of the experiment, it is suggested that membrane receptors could be one of the main targets by which RFR interacts with cells. An incoherent MF could block the interaction to a certain extent.     

Brain DNA damage and 70-kDa heat shock protein expression in CD1 mice exposed to extremely low frequency magnetic fields

Purpose:?The question of whether exposure to extremely low frequency magnetic fields (ELF-MF), may contribute to cerebral cancer and neurodegeneration is of current interest. In this study we investigated whether exposure to ELF-MF (50 Hz-1 mT) harms cerebral DNA and induces expression of 70-kDa heat shock protein (hsp70).

Materials and methods:?CD1 mice were exposed to a MF (50 Hz-1 mT) for 1 or 7 days (15 h/day) and sacrificed either at the end of exposure or after 24?h. Unexposed and sham-exposed mice were used as controls. Mouse brains were dissected into cerebral cortex-striatum, hippocampus and cerebellum to evaluate primary DNA damage and hsp70 gene expression. Food intake, weight gain, and motor activity were also evaluated.

Results:?An increase in primary DNA damage was detected in all cerebral areas of the exposed mice sacrificed at the end of exposure, as compared to controls. DNA damage, as can be evaluated by the comet assay, appeared to be repaired in mice sacrificed 24?h after a 7-day exposure. Neither a short (15?h) nor long (7 days) MF-exposure induced hsp70 expression, metabolic and behavioural changes.

Conclusions:?These results indicate that in?vivo ELF-MF induce reversible brain DNA damage while they do not elicit the stress response.     

Response of aquatic protists to electric field exposure

Purpose: To test the effects of short-term exposure of aquatic organisms to electric field (EF) with negligible magnetic component.

Materials and methods: We built a plate capacitor that served as a source of EF of strengths that can be found in nature near transmission lines. We exposed two cultured protist species Euglena viridis and Paramecium caudatum to EFs for 24?hours and monitored their abundance, morphology, intracellular superoxide anion (by dihydroethidium [DHE]), hydrogen peroxide by (H₂DCF) and lipid peroxidation (MDA) contents, catalase (CAT) and superoxide dismutase (SOD) activity.

Results: We found that even short-term exposure to low strength EF causes changes in population abundance, morphology and oxidative stress response in both species. As the EF strength increased, abundance of both species decreased. However, at weaker EFs, fission rates were seemingly promoted. We noted a decrease in size in both organisms in directions perpendicular to their fission planes correlated with EF strength. DHE and H₂DCF fluorescence intensity and SOD activity were higher in organisms exposed to the stronger EFs.

Conclusions: We suggest that the electric component of the field, rather than the magnetic, is the main cause of all the noted effects. As a result, aquatic organisms should be given greater importance in studies assessing the effects of EMFs in spite of the attenuating effects of water to EF strengths.     

The effect of a static magnetic field on the morphometric characteristics of neurosecretory neurons and corpora allata in the pupae of yellow mealworm Tenebrio molitor (Tenebrionidae)

Purpose:?The morphometric characteristics of A1 and A2 protocerebral neurosecretory neurons (cell and nuclei size, number of nucleoli in the nuclei); corpora allata size, nuclei size, cell number, were investigated in the pupae of yellow mealworm, Tenebrio molitor (L.), exposed to a strong static magnetic field of 320 mT maximum induction (10,000 times higher than the Earth's).

Materials and methods:?The experimental groups of Tenebrio molitor pupae were: A control group exposed only to natural magnetic field and sacrificed at the eighth day of pupal development (C); and pupae kept in a strong static magnetic field for eight days and then sacrificed (MF). Serial brain cross-sections were stained using the Alcian Blue Floxin technique. All the parameters were analyzed and measurements were performed using an image processing and analysis system (Leica, Cambridge, UK) linked to a Leica DMLB light microscope (program is QWin – Leica's Quantimet Windows-based image analysis tool kit).

Results:?The values of morphometric parameters of neurosecretory neurons and corpora allata were significantly increased after exposure of the pupae to the strong magnetic field.

Conclusions:?The strong magnetic field influence characteristics of protocerebral neurosecretory neurons and corpora allata in the late Tenebrio molitor pupae.     

In Vivo Enzyme Control Through a Strong Stationary Magnetic Field—the Case of Thymidine Kinase in Mouse Bone Marrow Cells

Summary

The influence of a strong homogeneous and stationary magnetic field (SMF) on the activity of the enzyme thymidine kinase (TdR-K) in bone marrow cells, and as a consequence of this on the incorporation of ¹²⁵I-labelled 5-iodo-2-deoxyuridine (¹²⁵IUdR) into DNA of mice and into isolated bone marrow cells in vitro, was assayed after exposure of immobilized mice. No effect could be elicited in moving mice, in cells in suspension or in enzyme in solution.

The response depended on the body temperature during exposure: at 27°C and 29°C there was an increase and at 37°C and 39·5°C a depression of enzyme activity. The TdR-K activity at low temperature increased with the field strength ranging from 0·2 to 1·4 T. Thirty minutes were required for full expression of the effect at 1·4 T; 5–10 min were needed after exposure for a return to base-line levels.

Mice were given total-body irradiation at a dose of 0·1 Gy ¹³⁷Cs gamma rays and then exposed immediately to a magnetic field at 1·4 T for 30 min at a body temperature of 27°C; gamma irradiation no longer inhibited the enzyme. Exposure to the magnetic field further removed from the time of gamma irradiation, did not negate the inhibitory effect of gamma irradiation.

The observed responses to given challenges in this complex system support the hypothesis that the magnetic field affects TdR-K activity by way of a mediating structure, such as a membrane.     

Effects of 21-kHz intermediate frequency magnetic fields on blood properties and immune systems of juvenile rats

Abstract

Purpose: Due to a lack of science-based evidence, we explored the effects of exposure to intermediate frequency magnetic fields (IF-MF) on experimental animals. We assessed several immunological parameters to determine the effect of exposure of the whole body to IF-MF.

Materials and methods: Male Sprague-Dawley rats (4–5 weeks old) were divided into three groups: Cage-control, sham, and 3.8-mT (rms) exposure groups. The animals were exposed to IF-MF at 21 kHz under fixed conditions in an acrylic holder. Exposure was performed for 1 h/day for 14 consecutive days. On the 15th day following the exposure, biochemical and hematological parameters in blood were analyzed. The effects of the exposure on immunological functions such as the cytotoxic activity of lymphocytes, chemotactic and phagocytic activity of granulocytes, and T (cluster of differentiation 4 [CD4] and cluster of differentiation 8 [CD8])-cell frequency were also examined.

Results: Hematological parameters were not affected by IF-MF exposure. Other immune functions such as the cytotoxic activity and phagocytic activity were not affected. Populations of T cells after exposure also did not show any significant differences. In blood biochemistry, there was significant difference in inorganic phosphorus level between sham and exposure group. However, this will not induce any pathophysiological status, because they were still within physiological range. Overall, no significant effect by exposure of IF-MF was observed under our experimental conditions.

Conclusions: Our results suggest that exposure to 21-kHz sinusoidal IF-MF at 3.8 mT for 1 h/day for 14 days did not affect immune function in juvenile rats.