The effect of long-term extremely low-frequency magnetic field on geometric and biomechanical properties of rats' bone.

Bone is composed of a mineral matrix reinforced by a network of collagen that governs the biomechanical functions of the skeletal system in the body. The purpose of the study was to investigate the possible effect of extremely low-frequency magnetic field (ELF-MF) on geometric and biomechanical properties of rats' bone. In this study, 30 male Sprague-Dawley rats were used. The rats were divided into three groups: two experimental and one control sham. The first and second experimental group (n=10) were exposed to 100 microT and 500 microT-MF during 10 months, 2 h a day, respectively, and the third (sham) (n=10) group was treated like experimental group except ELF-MF exposure in methacrylate boxes. After ELF-MF and sham exposure, geometric and the biomechanical properties of rats' bone, such as cross-sectional area of the femoral shaft, length of the femur, cortical thickness of the femur, ultimate tensile strength (maximum load), displacement, stiffness, energy absorption capacity, elastic modulus, and toughness of bone were determined. The geometric and biomechanical analyses showed that a significant decrease in rats exposed to 100 microT-MF in comparison to sham and 500 microT-MF exposed rats about the values of cross-sectional area of the femoral shaft (P<0.05). Maximum load increased in 100 muT-MF and 500 microT-MF exposed rats when compared to that of the sham rats (P<0.05). The cortical thickness of the femurs of MF-exposed rats (100 microT and 500 microT) were significantly decreased in comparison to that of sham groups' rats (P<0.05 and P<0.001). However, no significant differences were found in the other biomechanical endpoints between each other groups, such as: length of the femur, displacement, stiffness, energy absorption capacity, elastic modulus, and toughness of bone (P>0.05). These experiments demonstrated that 100 microT-MF and 500 microT-MF can affect biomechanical and geometrical properties of rats' bone.

Effect of mobile phone exposure on apoptotic glial cells and status of oxidative stress in rat brain.

The aim of this study was to investigate the effects of mobile phone exposure on glial cells in brain. The study carried out on 31 Wistar Albino adult male rats. The rat heads in a carousel exposed to 900 MHz microwave. For the study group (n:14), rats exposed to the radiation 2 h per day (7 days in a week) for 10 months. For the sham group (n:7), rats were placed into the carousel and the same procedure was applied except that the generator was turned off. For the cage control (n:10), nothing applied to rats in this group. In this study, rats were euthanized after 10 months of exposure periods and brains were removed. Brain tissues were immunohistochemically stained for the active (cleaved) caspase-3, which is a well-known apoptosis marker, and p53. The expression of the proteins was evaluated by a semi-quantitative scoring system. However, total antioxidative capacity (TAC), catalase, total oxidant status (TOS), and oxidative stress index were measured in rat brain. Final score for apoptosis in the exposed group was significantly lower than the sham (p < 0.001) and the cage control groups (p < 0.01). p53 was not significantly changed by the exposure (p > 0.05). The total antioxidant capacity and catalase in the experimental group was found higher than that in the sham group (p < 0.001, p < 0.05). In terms of the TOS and oxidative stress index, there was no statistically significant difference between exposure and sham groups (p > 0.05). In conclusion, the final score for apoptosis, total antioxidant capacity and catalase in rat brain might be altered by 900 MHz radiation produced by a generator to represent exposure of global systems for mobile communication (GSM) cellular phones.

Extremely low frequency magnetic fields cause oxidative DNA damage in rats.

PURPOSE: To detect the genotoxic effects of extremely low frequency (ELF) -magnetic fields (MF) on oxidative DNA base modifications [8-hydroxyguanine (8-OH-Gua), 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyGua) and 4,6-diamino-5-formamidopyrimidine (FapyAde)] in rat leucocytes, measured following exposure to ELF-MF. MATERIALS AND METHODS: After exposure to ELF-MF (50 Hz, 100 and 500 microT, for 2 hours/day during 10 months), DNA was extracted, and measurement of DNA lesions was achieved by gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/mass spectrometry (LC/MS). RESULTS: Levels of FapyAde, FapyGua and 8OHdG in DNA were increased by both 100 microT and 500 microT ELF-MF as compared to a cage-control and a sham group; however, statistical significance was observed only in the group exposed to 100 microT. CONCLUSION: This is the first study to report that ELF-MF exposure generates oxidatively induced DNA base modifications which are mutagenic in mammalian cells, such as FapyGua, FapyAde and 8-OH-Gua, in vivo. This may explain previous studies showing DNA damage and genomic instability. These findings support the hypothesis that chronic exposure to 50-Hz MF may be potentially genotoxic. However, the intensity of ELF-MF has an important influence on the extent of DNA damage.

Whole-body exposure of radiation emitted from 900 MHz mobile phones does not seem to affect the levels of anti-apoptotic bcl-2 protein.

The purpose of the present study was to investigate the anti-apoptotic bcl-2 protein in rat brain and testes after whole-body exposure to radiation emitted from 900 MHz cellular phones. Two groups (sham and experimental) of Sprague-Dawley rats of eight rats each were used in the study. Exposure began approximately 10 min after transferring into the exposure cages, a period of time when rats settled down to a prone position and selected a fixed location inside the cage spontaneously. For the experimental group, the phones were in the speech condition for 20 min per day for 1 month. The same procedure was applied to the sham group rats, but the phones were turned off. Immunohistochemical staining of bcl-2 was performed according to the standardized avidin-biotin complex method. The results of this study showed that 20 min of the radiation emitted from 900 MHz cellular phones did not alter anti-apoptotic bcl-2 protein in the brain and testes of rats. We speculate that bcl-2 may not be involved in the effects of radiation on the brain and testes of rats.

Mobile phone exposure does not induce apoptosis on spermatogenesis in rats.

BACKGROUND: Some studies have reported that microwave radiation can have adverse effects on reproduction. Therefore, the purpose of this study was to investigate the apoptosis-inducing effect of mobile phone exposure on spermatogonia in seminiferous tubules. METHODS: The study was carried out on 31 Wistar albino adult male rats. The rats were separated into three groups in this study (cage control: 10, sham group: 7, and exposed group: 14). For the study group, rats were exposed to radiation 2 h/day (7 days/week) for 10 months. For the sham group, rats were placed into the carousel and the same procedure was applied except that the generator was turned off. For the cage control, nothing was applied to the rats in this group and they completed their life cycle in the cage during the study period. In this study, rats were sacrificed after 10 months of exposure and their testes were taken. Testes tissue was immunohistochemically stained for the active (cleaved) caspase-3. Positively stained cells were counted in up to ten different areas, and the frequency of positive cells was determined in percentage. Scoring was done by taking into account both the intensity of staining and the distribution of positively stained cells. Therefore, protein expression was evaluated by a semiquantitative scoring system. RESULTS: The final score for apoptosis of testes in the exposed group was not statistically significant according to the sham and the cage control groups (p>0.05). CONCLUSIONS: The results of this study showed that 2 h/day (7 days/week) exposure of 900 MHz radiation over a period of 10 months does not affect the active (cleaved) caspase-3 levels in testes, a well-known feature of typical apoptosis.

Alteration of nitric oxide production in rats exposed to a prolonged, extremely low-frequency magnetic field.

The purpose of this study is to investigate the possible effect of an extremely low-frequency magnetic field (ELF-MF) on nitric oxide (NO) level. In this study, 27 male Sprague-Dawley rats were used. The rats were divided into three groups: two experimental and one control (sham-exposed). The first and second experimental group (n = 10) were exposed to 100 microT and 500 microT ELF-MF during 10 months, 2 h a day, respectively, and the third (n = 7) group was treated like an experimental group except for ELF-MF exposure in methacrylate boxes. After ELF-MF and sham exposure, serum nitrite levels were measured by Griess reaction. A significant reduction was observed in nitrite levels among the first and second experimental groups of rats and sham-exposed rats after exposure for 10 months, 2 h a day, to ELF-MF of 100 and 500 microT (p < 0.01). These results suggest that prolonged ELF-MF exposure at intensities of exposure limits, determined by ICNIRP for public and occupational, may reduce NO production probably affected by NO generation pathways.

Effect of ELF magnetic fields on lipid peroxidation, sperm count, p53, and trace elements.

BACKGROUND: Some epidemiological and laboratory studies suggest a possible connection between extremely low-frequency (ELF) magnetic fields and certain illnesses, such as cancer, immune suppression, as well as reproductive toxic effects and abnormalities. Therefore, the aim of this study was to investigate the effects of ELF magnetic fields (1.35 mT) on sperm count, malondialdehyde concentration, the histology of such organs as the testes, brain, liver, and kidney tissues, p53 immunoreactivity of bone marrow, and the serum concentrations of Cu2+, Zn2+, Mn2+, and Fe3+ in rats. MATERIAL/METHODS: Sixteen Sprague-Dawley male rats were divided into two groups. The rats in the experimental group were exposed to an ELF magnetic field 2 hr/day for 2 months (7 days a week). The rats in the control group were not exposed to the ELF magnetic field. The exposure was performed in a Faraday cage (130 x 65 x 80 cm) with grounded shielding against the electric component. The Mann-Whitney U-test was used for the statistical analysis of the data. RESULTS: Magnetic field measurements showed that, under the experimental conditions, the magnetic field-exposure system produced a stable flux density of 1.35+/-0.018 mT and a stable frequency of 50 Hz, with negligible harmonics and no transients. However, no statistically significant alteration was observed in the parameters measured in this study except in Mn2+ concentrations (p<0.001). CONCLUSIONS: The present study found no evidence of an adverse effect of ELF magnetic fields on the measured parameters except for significantly increased Mn2+ concentrations (p<0.001).

Effect of 50-Hz 1-mT magnetic field on the uterus and ovaries of rats (electron microscopy evaluation).

BACKGROUND: The aim of this study was to investigate the effect of extremely low frequency magnetic fields (ELFMF) on the uterus and ovary of rats. MATERIAL/METHODS: Forty-eight female Wistar albino rats were divided into two groups, one for 50 and the other for 100 days of exposure. Each group was further divided into two groups, one sham exposed (n=12) and the other the experimental group (n=12). The experimental rats were exposed to 50-Hz 1-mT ELFMF for three hours/day for 50 or 100 days. The sham groups of rats were kept under the same circumstances without applying ELFMF. Electron microscopic examination was performed to evaluate the ovaries and uterus. RESULTS: Ultrastructural dissolution, decrease in cell organelles, cavities in cells, heterochromative appearance, and typical structural loss of the nucleus were observed in germinal epithelial cells of the rat ovaries in the 50-days ELFMF exposure group. Ultrastructural alterations in germinal epithelium and tunica albuginea of ovaries, irregularity in nucleus and nucleolus, increase in lipid vacuoles of cell cytoplasm and reduction in organelles were observed in rat ovaries in the 100-days ELFMF exposure group. Similar alterations were observed in uterus. Malondialdehyde concentration (MDA) of the ovaries and uterus increased in rats of the two exposure groups (p<0.001). CONCLUSIONS: The results of the study showed that 50 and 100 days of exposure to a 1-mT ELFMF can cause alterations at the cellular level and in MDA concentration.

Oxidative DNA damage in rats exposed to extremely low frequency electro magnetic fields.

Extremely low frequency (ELF) electromagnetic field (EMF) is thought to prolong the life of free radicals and can act as a promoter or co-promoter of cancer. 8-hydroxy-2'-deoxyguanosine (8OHdG) is one of the predominant forms of radical-induced lesions to DNA and is a potential tool to asses the cancer risk. We examined the effects of extremely low frequency electro magnetic field (ELF-EMF) (50 Hz, 0.97 mT) on 8OHdG levels in DNA and thiobarbituric acid reactive substances (TBARS) in plasma. To examine the possible time-dependent changes resulting from magnetic field, 8OHdG and TBARS were quantitated at 50 and 100 days. Our results showed that the exposure to ELF-EMF induced oxidative DNA damage and lipid peroxidation (LPO). The 8OHdG levels of exposed group (4.39+/-0.88 and 5.29+/-1.16 8OHdG/dG.10(5), respectively) were significantly higher than sham group at 50 and 100 days (3.02+/-0.63 and 3.46+/-0.38 8OHdG/dG.10(5)) (p<0.001, p<0.001). The higher TBARS levels were also detected in the exposure group both on 50 and 100 days (p<0.001, p<0.001). In addition, the extent of DNA damage and LPO would depend on the exposure time (p<0.05 and p<0.05). Our data may have important implications for the long-term exposure to ELF-EMF which may cause oxidative DNA damage.