Medical/biological study (experimental study)

ELF magnetic fields do not affect cell survival and DNA damage induced by ultraviolet B med./bio.

By: Mizuno K, Narita E, Yamada M, Shinohara N, Miyakoshi J

Published in: Bioelectromagnetics 2014; 35 (2): 108-115

Aim of study (acc. to author)

To determine whether exposure of skin derived cells to an extremely low frequency magnetic field alters the cell viability and the DNA damage induced by ultraviolet B.

Background/further details

Xeroderma pigmentosum is a rare hereditary disease of the skin characterized by a low ability to repair DNA damage induced by ultraviolet radiation. The XP2OS(SV)-cell line was established from xeroderma pigmentosum skin. The W138VA13-cell line was used as a control group.
First, the cells were radiated with ultraviolet B of different intensities (0, 20, 40, 60 or 80 J/m²). Afterwards, the cells were exposed to an extremely low frequency field or sham exposed for 1, 3, or 24 hours.

Endpoint

genotoxicity/mutation: DNA damage
cell viability/cell division/proliferation: cell viability

Exposure

Exposure	Parameters
Exposure 1: 60 Hz Exposure duration: continuous for 1, 3 or 24 hours	magnetic flux density: 5 mT electric field strength: 0.047 V/m (cell culture dish (100 mm)) electric field strength: 0.007 V/m (24-well plate)

Exposure 1

Main characteristics

Frequency	60 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	continuous for 1, 3 or 24 hours

Exposure setup

Exposure source	Helmholtz coils
Setup	exposure system consisted of CO₂ incubator with a built-in magnetic field, constructed with Helmholtz coils (inner diameter 250 mm, length 160 mm, 128 turns), a slide regulator and a thermo controller; temperature in incubtaor: 37 ± 0.2°C; interior and exterieur were shielded by silicon steel and Permalloy C, respectively; direction of magnetic field was vertical
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	5 mT	-	measured	-	-
electric field strength	0.047 V/m	-	calculated	-	cell culture dish (100 mm)
electric field strength	0.007 V/m	-	calculated	-	24-well plate

Additional parameter details

ambient magnetic fields in incubators were less than 0.5 µT; static magnetic field, other than geomagnetic, were undetectable at these exposure and non exposure units (<0.1 µT)

Reference articles

Sakurai T et al. (2004): An extremely low frequency magnetic field attenuates insulin secretion from the insulinoma cell line, RIN-m
Miyakoshi J et al. (1996): Exposure to magnetic field (5 mT at 60 Hz) does not affect cell growth and c-myc gene expression
Misakian M et al. (1993): Biological, physical, and electrical parameters for in vitro studies with ELF magnetic and electric fields: a primer

Exposed system:

intact cell/cell culture
W138VA13 (human embryo lung-derived cells) and XP2OS(SV) (human xeroderma pigmentosum skin-derived cells)

Methods Endpoint/measurement parameters/methodology

genotoxicity/mutation: DNA damage (via cyclobutane pyrimidine dimer formation and 6,4-photoproduct formation, ELISA)
cell viability/cell division/proliferation: cell viability (WST-1-assay (based on tetrazolium), spectrophotometry)

Investigated system:

DNA/RNA
intact cell/cell culture

Time of investigation:

after exposure

Main outcome of study (acc. to author)

In both cell lines, ultraviolet radiation reduced the cell viability and induced DNA damage. However, no significant influence of magnetic field exposure on the cell viability and DNA damage was observed.
The data indicate that the exposure to extremely low frequency magnetic fields had no influence on the cell viability and the DNA damage induced by ultraviolet B.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

not stated/no funding

Burgos-Molina AM et al. (2020): Effect of low frequency magnetic field on efficiency of chromosome break repair
Markkanen A et al. (2010): A Study on the Effects of 50 Hz Magnetic Fields on UV-induced Radical Reactions in Murine Fibroblasts
Juutilainen J (2008): Do electromagnetic fields enhance the effects of environmental carcinogens?
Juutilainen J et al. (2006): Do extremely low frequency magnetic fields enhance the effects of environmental carcinogens? A meta-analysis of experimental studies
Zmyslony M et al. (2004): Effects of in vitro exposure to power frequency magnetic fields on UV-induced DNA damage of rat lymphocytes
Nindl G et al. (2002): Effect of ultraviolet B radiation and 100 Hz electromagnetic fields on proliferation and DNA synthesis of Jurkat cells
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Markkanen A et al. (2001): Effects of 50 Hz magnetic field on cell cycle kinetics and the colony forming ability of budding yeast exposed to ultraviolet radiation
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Ager DD et al. (1992): Effect of 60-Hz magnetic fields on ultraviolet light-induced mutation and mitotic recombination in Saccharomyces cerevisiae
Whitson GL et al. (1986): Effects of extremely low frequency (ELF) electric fields on cell growth and DNA repair in human skin fibroblasts