Comet assay to evaluate DNA damage caused by magnetic fields

Ahuja, Y.R.; Bhargava, Arpit; Sircar, Sarthok; Rizwani, W.; Lima, Sarah Azoubel; Devadas, A.H.; Bhargava, S.C.

doi:10.1109/icemic.1997.669812

Cited by 7 publications

(6 citation statements)

References 10 publications

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“…In vitro exposure: freshly collected or cultured human cells. Ahuja et al [1997] used a source of variable alternate current (AC) supply and a set of six identical air cored coils kept in a special box to expose freshly collected cells to MF. Comet assay tail length analysis showed a significant increase in SSB at each flux density tested.…”

Section: Dna Single and Double Strand Breaks (Ssb And Dsb)mentioning

confidence: 99%

Controversial cytogenetic observations in mammalian somatic cells exposed to extremely low frequency electromagnetic radiation: A review and future research recommendations

Vijayalaxmi

Obe

2005

Bioelectromagnetics

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During the years 1990-2003, a large number of investigations were conducted using animals, cultured rodent and human cells as well as freshly collected human blood lymphocytes to determine the genotoxic potential of exposure to nonionizing radiation emitted from extremely low frequency electromagnetic fields (EMF). Among the 63 peer reviewed scientific reports, the conclusions from 29 studies (46%) did not indicate increased damage to the genetic material, as assessed from DNA strand breaks, incidence of chromosomal aberrations (CA), micronuclei (MN), and sister chromatid exchanges (SCE), in EMF exposed cells as compared with sham exposed and/or unexposed cells, while those from 14 investigations (22%) have suggested an increase in such damage in EMF exposed cells. The observations from 20 other studies (32%) were inconclusive. This study reviews the investigations published in peer reviewed scientific journals during 1990-2003 and attempts to identify probable reason(s) for the conflicting results. Recommendations are made for future research to address some of the controversial observations.

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Section: Dna Single and Double Strand Breaks (Ssb And Dsb)mentioning

confidence: 99%

Controversial cytogenetic observations in mammalian somatic cells exposed to extremely low frequency electromagnetic radiation: A review and future research recommendations

Vijayalaxmi

Obe

2005

Bioelectromagnetics

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“…An increase in DNA single-strand breaks was observed after 2 hr of exposure to the magnetic field at flux density of ≥ 0.1 millitesla (mT), whereas an increase in double-strand breaks was observed at ≥ 0.25 mT. Using the microgel electrophoresis assay, Ahuja et al (1997Ahuja et al ( , 1999, Phillips et al (1997), Svedenstal et al (1999aSvedenstal et al ( , 1999b, and Zmyslony et al (2000) have also reported an increase in DNA strand breaks in cells after magnetic field exposure. In studies by Ahuja et al (1997Ahuja et al ( , 1999, an increase in DNA single-strand breaks in human lymphocytes was observed after 1 hr of exposure to a 50-Hz magnetic field at 0.2-2 mT, whereas in the study by Phillips et al (1997), an increase in single-strand breaks was observed in human Molt-4 cells after 24 hr of exposure to a 60-Hz magnetic field at 0.1 mT.…”

mentioning

confidence: 99%

“…Using the microgel electrophoresis assay, Ahuja et al (1997Ahuja et al ( , 1999, Phillips et al (1997), Svedenstal et al (1999aSvedenstal et al ( , 1999b, and Zmyslony et al (2000) have also reported an increase in DNA strand breaks in cells after magnetic field exposure. In studies by Ahuja et al (1997Ahuja et al ( , 1999, an increase in DNA single-strand breaks in human lymphocytes was observed after 1 hr of exposure to a 50-Hz magnetic field at 0.2-2 mT, whereas in the study by Phillips et al (1997), an increase in single-strand breaks was observed in human Molt-4 cells after 24 hr of exposure to a 60-Hz magnetic field at 0.1 mT. Svedenstal et al observed an increase in DNA double-strand breaks in brain cells of mice after 32 days of exposure to magnetic fields of 7.5 µT (Svedenstal et al 1999a) and after 14 days of exposure at 0.5 mT (Svedenstal et al 1999b).…”

mentioning

confidence: 99%

Magnetic-field-induced DNA strand breaks in brain cells of the rat.

Lai

Singh

2004

Environ Health Perspect

275

172

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In previous research, we found that rats acutely (2 hr) exposed to a 60-Hz sinusoidal magnetic field at intensities of 0.1-0.5 millitesla (mT) showed increases in DNA single-and double-strand breaks in their brain cells. Further research showed that these effects could be blocked by pretreating the rats with the free radical scavengers melatonin and N-tert-butyl-α-phenylnitrone, suggesting the involvement of free radicals. In the present study, effects of magnetic field exposure on brain cell DNA in the rat were further investigated. Exposure to a 60-Hz magnetic field at 0.01 mT for 24 hr caused a significant increase in DNA single-and double-strand breaks. Prolonging the exposure to 48 hr caused a larger increase. This indicates that the effect is cumulative. In addition, treatment with Trolox (a vitamin E analog) or 7-nitroindazole (a nitric oxide synthase inhibitor) blocked magnetic-field-induced DNA strand breaks. These data further support a role of free radicals on the effects of magnetic fields. Treatment with the iron chelator deferiprone also blocked the effects of magnetic fields on brain cell DNA, suggesting the involvement of iron. Acute magnetic field exposure increased apoptosis and necrosis of brain cells in the rat. We hypothesize that exposure to a 60-Hz magnetic field initiates an iron-mediated process (e.g., the Fenton reaction) that increases free radical formation in brain cells, leading to DNA strand breaks and cell death. This hypothesis could have an important implication for the possible health effects associated with exposure to extremely low-frequency magnetic fields in the public and occupational environments.

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“…Single strand DNA breaks have been reported in Molt 4 T-lymphoblastoid cells [11]. A dose dependent increase in DNA single strand breaks was observed in human leukocytes exposed to 50 Hz magnetic fields [12]. The latest published data provided evidence suggesting that ELF-EMF interfere with the DNA repair process leading to accumulation of damaged DNA in cells [13].…”

Section: Introductionmentioning

confidence: 81%

“…Single strand DNA breaks have been reported [11]. A dose dependent increase in DNA single strand breaks was observed in human leukocytes exposed to 50 Hz magnetic fields [12]. It was also stated [11] that exposure of Molt 4 T-lymphoblastoid cells to a 100 T, 60 Hz sinusoidal magnetic fields leads to decreased activity of the DNA repair enzyme, poly (ADP-ribose) polymerase, and increased DNA fragmentation in the presence of the DNA damaging agent, etoposide.…”

Section: Discussionmentioning

confidence: 99%

Viability of unstimulated lymphocytes exposed to extremely low frequency electromagnetic fields is dependent on intensity

Rajendra¹,

Sujatha²,

Sashidhar³

et al. 2012

Biodiscovery

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The cell viability and DNA damage in unstimulated sheep primary lymphocytes subjected to different extremely low electromagnetic field intensities (5, 50 and 100 µT; 50 Hz) were studied with special emphasis on apoptosis. Sheep primary lymphocytes cultured in RPMI, supplemented with 10% FBS in the absence of mitogens, were exposed till 16 h. The cell viability assessment by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyl tetrazolium bromide (MTT) assay showed a dose dependent enhancement of viability at 16 h. Further, quantitative DNA laddering and flow cytometric analysis showed a significant decrease in apoptosis of the cells subjected to 100 (p<0.01) and 50 µT (p<0.05) for 16 h as compared to control group. There was a statistically significant decrease (p<0.01) in the specific activity of caspase 9 at 100 µT in cells exposed for 16 h. However, no enhancement of DNA damage was observed at 5, 50 and 100 µT as evidenced by comet assay. Comet assay also confirmed the decreased cell death of exposed cells (100 µT). Experimental data suggests decreased apoptosis at 100 µT (50 Hz), possibly by the suppression of caspase 9 activity leading to the enhanced cell viability. Effect of ELF-EMF on primary lymphocytesBioDiscovery | www.biodiscoveryjournal.co.uk

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Comet assay to evaluate DNA damage caused by magnetic fields

Cited by 7 publications

References 10 publications

Controversial cytogenetic observations in mammalian somatic cells exposed to extremely low frequency electromagnetic radiation: A review and future research recommendations

Controversial cytogenetic observations in mammalian somatic cells exposed to extremely low frequency electromagnetic radiation: A review and future research recommendations

Magnetic-field-induced DNA strand breaks in brain cells of the rat.

Viability of unstimulated lymphocytes exposed to extremely low frequency electromagnetic fields is dependent on intensity

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