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EMF Study
(Database last updated on Sep 25, 2022)

ID Number 1997
Study Type In Vivo
Model 900 MHz (GSM) exposure of mammals and cells in culture (SHG44 glioblastoma cells) alone and in combination with gamma rays or bleomycin and analysis of apoptosis, stress response, mitochondrial function and DNA damage including germ cell damage.
Details

SHG44 glioblastoma cells were exposed to 900 MHz (GSM) for 2 h/day, 3 days at power densities of 2, 4, or 6 mW/cm2, and either with or without co-exposure to gamma rays. The authors report RF synergized with gamma rays and enhanced apoptotic death, hsp70 expression, and the production of reactive oxygen species and decreased superoxide dismutase (SOD) levels. Authors' abstract (#4971): Xu et al. (2009): OBJECTIVE: To investigate radiation protection and possible mechanisms of low intensity microwave on gamma-ray exposed mice. METHODS: 96 healthy Kunming mice were randomly divided into the following four groups: normal control, microwave (120 microW/cm(2), 900 MHz), gamma-ray irradiation (5 Gy), combined exposure of microwave and gamma-ray (120 microW/cm(2) + 5 Gy). The microwave group and combined group were exposed to 120 microW/cm(2) microwave firstly, 1 h/d, for 14 days. Then the ionization and combined group were exposed to 5 Gy (60)Co gamma-ray irradiation on the 15th day. Animals were sacrificed on the third, 6th, 9th and 12th day after irradiation. The sternum and spleen paraffin section were produced, and the histological changes were observed. Apoptosis rate of mice splenic cells in each group was examined by flow cytometry, and serum concentration of antioxidase and lipid peroxide was detected at the same time. RESULTS: Bone marrow was obviously injured either by radiation or microwave exposure, characterized by undergoing four-phase lesions, namely apoptosis-necrosis, void, regeneration and recovery phase. Compared with the gamma-ray group, the pathological changes in combined group were slighter and the recovery was quicker. The pathological injuries of spleen were similar to that of bone marrow. Injuries in the combined group were slighter than gamma-ray group. It showed that apoptosis rate of splenic cells in combined group was significantly lower on the 6th and 9th day after gamma-ray radiation (23.02% +/- 15.18%, 25.37% +/- 11.62% respectively) from FCM results. Assays of oxidative damages suggested that serum superoxide dismutase (SOD) level in combined group increased while lipid peroxide level decreased significantly (P < 0.05). CONCLUSION: Low intensity microwave may exert protection effects on injuries induced by ionizing radiation. The underlying mechanisms might be related with suppression on the hematopoietic cells apoptosis induced by gamma-ray radiation, inhibition of oxidative damages, and thus enhanced reconstruction of the hematopoietic system. AUTHORS' ABSTRACT: Jiang et al. 2012 (IEEE #5500): The phenomenon of adaptive response (AR) in animal and human cells exposed to ionizing radiation is well documented in scientific literature. We have examined whether such AR could be induced in mice exposed to non-ionizing radiofrequency fields (RF) used for wireless communications. Mice were pre-exposed to 900 MHz RF at 120 µW/cm(2) power density for 4 hours/day for 1, 3, 5, 7 and 14 days and then subjected to an acute dose of 3 Gy ³-radiation. The primary DNA damage in the form of alkali labile base damage and single strand breaks in the DNA of peripheral blood leukocytes was determined using the alkaline comet assay. The results indicated that the extent of damage in mice which were pre-exposed to RF for 1 day and then subjected to ³-radiation was similar and not significantly different from those exposed to ³-radiation alone. However, mice which were pre-exposed to RF for 3, 5, 7 and 14 days showed progressively decreased damage and was significantly different from those exposed to ³-radiation alone. Thus, the data indicated that RF pre-exposure is capable of inducing AR and suggested that the pre-exposure for more than 4 hours for 1 day is necessary to elicit such AR. AUTHORS' ABSTRACT: Zong et al. 2015 (IEEE #5854): Purpose: To determine whether mice exposed to radiofrequency fields (RF) and then injected with a radiomimetic drug, bleomycin (BLM), exhibit adaptive response and provide some mechanistic evidence for such response. Materials and methods: Adult mice were exposed to 900 MHz RF at 120 ¼W/cm2 power density for 4 hours/day for 7 days. Immediately after the last exposure, some mice were sacrificed while the others were injected with BLM 4 h later. In each animal: (i) The primary DNA damage and BLM-induced damage as well as its repair kinetics were determined in blood leukocytes; and (ii) the oxidative damage was determined from malondialdehyde (MDA) levels and the antioxidant status was assessed from superoxide dismutase (SOD) levels in plasma, liver and lung tissues. Results: There were no indications for increased DNA and oxidative damages in mice exposed to RF alone in contrast to those treated with BLM alone. Mice exposed to RF+ BLM showed significantly: (a) reduced BLM-induced DNA damage and that remained after each 30, 60, 90, 120 and 150 min repair time, and (b) decreased levels of MDA in plasma and liver, and increased SOD level in the lung. Conclusions: The overall data suggested that RF exposure was capable of inducing adaptive response and mitigated BLM-induced DNA and oxidative damages by activating certain cellular processes. AUTHORS' ABSTRACT: Zhu et al. 2015 (IEEE #6128): Adult male ICR mice were exposed to continuous wave 900MHz radiofrequency fields (RF) at 1.6mW/cm(2) power intensity (whole body average specific absorption rate of 0.731W/kg) for 4 hour/day for 15 days. At the end of exposure, each mouse was caged with 3 mature virgin female mice for mating. After 7 days, each male mouse was transferred to a fresh cage and mated with a second batch of 3 females. This process was repeated for a total of 4 consecutive weeks. Sham exposed male mice and those subjected to an acute 2Gy ³-irradiation (GR) were handled similarly and used as un-exposed and positive controls, respectively. All females were sacrificed on the 18th day of gestation and presumptive mating and, the contents in their uteri were examined. The overall observations during the 4 weeks of mating indicated that the un-exposed female mice mated to RF-exposed male mice showed no significant differences in the percentage of pregnancies, total implants, live implants and dead implants when compared with those mated with sham-exposed mice. In contrast, female mice mated with GR-exposed males showed a consistent pattern of significant differences in the above indices in each and all 4 weeks of mating. Thus, the data indicated an absence of mutagenic potential of RF exposure in the germ cells of male mice. AUTHORS' ABSTRACT: Sun et al. 2017 (IEEE 6719): HL-60 cells, derived from human promyelocytic leukemia, were exposed to continuous wave 900MHz radiofrequency fields (RF) at 120¼W/cm2 power intensity for 4h/day for 5 consecutive days to examine whether such exposure is capable damaging the mitochondrial DNA (mtDNA) mediated through the production of reactive oxygen species (ROS). In addition, the effect of RF exposure was examined on 8-hydroxy-2'-dexoyguanosine (8-OHdG) which is a biomarker for oxidative damage and on the mitochondrial synthesis of adenosine triphosphate (ATP) which is the energy required for cellular functions. The results indicated a significant increase in ROS and significant decreases in mitochondrial transcription factor A, mtDNA polymerase gamma, mtDNA transcripts and mtDNA copy number in RF-exposed cells compared with those in sham-exposed control cells. In addition, there was a significant increase in 8-OHdG and a significant decrease in ATP in RF-exposed cells. The response in positive control cells exposed to gamma radiation (GR, which is also known to induce ROS) was similar to those in RF-exposed cells. Thus, the overall data indicated that RF exposure was capable of inducing mtDNA damage mediated through ROS pathway which also induced oxidative damage. Prior-treatment of RF- and GR-exposed the cells with melatonin, a well-known free radical scavenger, reversed the effects observed in RF-exposed cells.

Findings Effects
Status Completed With Publication
Principal Investigator Sowchow Univ, Suzhou, China
Funding Agency Nat'l Res Prog, China
Country CHINA
References
  • Xu, Q et al. Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi, (2009) 27:520-524
  • Cao, Y et al. Zhonghua Lao Dong Wei Sheng Zhi Ye Bing Za Zhi, (2009) 27:525-529
  • Cao, Y et al. J Toxicol Environ Health A, (2009) 72:727-732
  • Jiang, B et al. PLoS One., (2012) 7(2):e32040. doi:10.1371/journal.pone.0032040-(4 pages)
  • Zong, C et al. International Journal of Radiation Biology., (2015) 91:270-276
  • Zhu, S et al. Mutat Res Genet Toxicol Environ Mutagen., (2015) 792:53-57
  • Sun, Y et al. Mutat Res., (2017) 797-799:7-14
  • Cao, Y et al. International journal of environmental research and public health., (2014) 11:4441-4448
  • Xie, W et al. Front. Public Health., (2021) 9:724239-doi.org/10.3389/fpubh.2021.724239
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