Home
Medical/biological study (experimental study)

8-oxoG DNA Glycosylase-1 Inhibition Sensitizes Neuro-2a Cells to Oxidative DNA Base Damage Induced by 900 MHz Radiofrequency Electromagnetic Radiation.

Published in: Cell Physiol Biochem 2015; 37 (3): 1075-1088

Aim of study (acc. to author)

The genotoxic effects of exposure of neuroblastoma cells to a 900 MHz electromagnetic field (GSM) and the role of the oxoguanine glycosylase should be investigated.
Background/further details: Oxoguanine glycosylase (also called 8-oxoG DNA glycosylase-1) is the major protective enzyme against the mutagenic effects of 8-oxoguanine (similar to 8-OHdG). 8-Oxoguanine DNA lesions result from reactive oxygen species. If the oxoguanine glycosylase plays a role in radiofrequency electromagnetic field-induced oxidative DNA damage should be investigated in the study. Therefore, the enzyme was partly disabled via transfection with siRNA ("gene silencing").
Cells were exposed to 1) SAR of 0.5 W/kg, 2) SAR of 1 W/kg, 3) SAR of 2 W/kg. For each of these groups, a separate sham exposure was conducted. Additionally, a negative control and a positive control were conducted. Groups 2 and 3 and their respective sham exposure groups were also investigated with silencing of the oxoguanine glycosylase.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Modulation type: pulsed
Exposure duration: continuous for 24 hours
Exposure 2: 900 MHz
Modulation type: pulsed
Exposure duration: continuous for 24 hours
Exposure 3: 900 MHz
Modulation type: pulsed
Exposure duration: continuous for 24 hours
Exposure 1
Main characteristics
Frequency 900 MHz
Type
Exposure duration continuous for 24 hours
Modulation
Modulation type pulsed
Additional info GSM Talk signal
Exposure setup
Exposure source
Chamber petri dishes in two rectangular chambers placed inside the same incubator with a common location for the air inlet to maintain the same environmental conditions (37°C, 5% CO2)
Setup one of the chambers was excited by an EMF signal mimicking the basic pulse structure of the GSM Talk signal at 900 MHz and the other was used for sham exposure (random choice); 8 petri dishes with cell monolayers were arranged in two towers of four dishes each; the temperature increased by 0.02°C/(W/kg) of the average SAR value during exposure; the temperature difference between exposed and sham-exposed chambers did not exceed 0.1°C
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 0.5 W/kg mean - - SAR variability < 6%
Exposure 2
Main characteristics
Frequency 900 MHz
Type
Exposure duration continuous for 24 hours
Modulation
Modulation type pulsed
Additional info GSM Talk signal
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 1 W/kg mean - - SAR variability < 6%
Exposure 3
Main characteristics
Frequency 900 MHz
Type
Exposure duration continuous for 24 hours
Modulation
Modulation type pulsed
Additional info GSM Talk signal
Exposure setup
Exposure source
Sham exposure A sham exposure was conducted.
Parameters
Measurand Value Type Method Mass Remarks
SAR 2 W/kg mean - - SAR variability < 6%
Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated material:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Without oxoguanine glycosylase silencing, only group 3 (2 W/kg) showed a significantly increased amount of DNA base damage and reactive oxygen species in exposed cells compared to sham exposed cells.
Oxoguanine glycosylase silencing caused significantly increased amounts of DNA base damage in exposed cells of groups 2 (1 W/kg) and 3 compared to exposed cells of the respective group without oxoguanine glycosylase silencing.
No effects on DNA strand breaks and on cell viability were found in any group with or without oxoguanine glycosylase silencing.
The authors conclude that exposure of neuroblastoma cells to a 900 MHz electromagnetic field (GSM) might induce oxidative DNA base damage. The oxoguanine glycosylase could play a critical role in the protection of cells against this damage.
Study character:

Study funded by

  • National Basic Research Program of China
  • National Natural Science Foundation (NSFC), China

Related articles

  • Hou Q et al. (2015): Oxidative changes and apoptosis induced by 1800-MHz electromagnetic radiation in NIH/3T3 cells.
  • Kang KA et al. (2014): Effects of combined radiofrequency radiation exposure on levels of reactive oxygen species in neuronal cells.
  • Zeni O et al. (2012): Radiofrequency radiation at 1950 MHz (UMTS) does not affect key cellular endpoints in neuron-like PC12 cells.
  • Lu YS et al. (2012): Reactive Oxygen Species Formation and Apoptosis in Human Peripheral Blood Mononuclear Cell Induced by 900 MHz Mobile Phone Radiation.
  • de Gannes FP et al. (2011): Effect of Exposure to the Edge Signal on Oxidative Stress in Brain Cell Models.
  • Xu S et al. (2010): Exposure to 1800 MHz radiofrequency radiation induces oxidative damage to mitochondrial DNA in primary cultured neurons.
  • Luukkonen J et al. (2010): Combined effects of 872 MHz radiofrequency radiation and ferrous chloride on reactive oxygen species production and DNA damage in human SH-SY5Y neuroblastoma cells.
  • De Iuliis GN et al. (2009): Mobile phone radiation induces reactive oxygen species production and DNA damage in human spermatozoa in vitro.
  • Cao Y et al. (2009): 900-MHz microwave radiation enhances gamma-ray adverse effects on SHG44 cells.
  • Del Vecchio G et al. (2009): Effect of radiofrequency electromagnetic field exposure on in vitro models of neurodegenerative disease.
  • Luukkonen J et al. (2009): Enhancement of chemically induced reactive oxygen species production and DNA damage in human SH-SY5Y neuroblastoma cells by 872 MHz radiofrequency radiation.
  • Hoyto A et al. (2008): Proliferation, Oxidative Stress and Cell Death in Cells Exposed to 872 MHz Radiofrequency Radiation and Oxidants.
  • Speit G et al. (2007): Genotoxic effects of exposure to radiofrequency electromagnetic fields (RF-EMF) in cultured mammalian cells are not independently reproducible.
  • Sakuma N et al. (2006): DNA strand breaks are not induced in human cells exposed to 2.1425 GHz band CW and W-CDMA modulated radiofrequency fields allocated to mobile radio base stations.
  • Li L et al. (2001): Measurement of DNA damage in mammalian cells exposed in vitro to radiofrequency fields at SARs of 3-5 W/kg.
  • Malyapa RS et al. (1997): Measurement of DNA damage after exposure to electromagnetic radiation in the cellular phone communication frequency band (835.62 and 847.74 MHz).