Medical/biological study (experimental study)

Comparison of the reactions to stress produced by X-rays or electromagnetic fields (50Hz) and heat: induction of heat shock genes and cell cycle effects in human cells med./bio.

By: Tokalov SV, Pieck S, Gutzeit HO

Published in: J Appl Biomed 2003; 1 (2): 85-93

Aim of study (acc. to author)

To analyze the cellular response to the stressors X-radiation, extremely low frequency magnetic fields and/or heat shock in a human leukemia cell line.

Background/further details

Cells were subjected to the following conditions: 1.) X-radiation (5 Gy at a dose rate of 1.2 Gy/min), 2.) heat shock (41°C for 30 minutes), 3.) magnetic field, 4.) X-radiation + heat shock, 5.) magnetic field + heat shock, 6.) X-radiation + magnetic field and 7.) control group.

Endpoint

molecular biosynthesis: gene expression of heat shock proteins
cell viability/cell division/proliferation: cell cycle distribution; cell proliferation

Exposure

- 50/60 Hz
- magnetic field
- also other exposures without EMF
- co-exposure

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: continuous for 30 min.	magnetic flux density: 60 µT (± 0.2 µT)

General information

cells were treated with 1) X-rays 2) heat shock 3) 50 Hz EMF 4) X-rays + heat shock 5) 50 Hz EMF + heat shock 6) X-rays + 50 Hz EMF

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	continuous for 30 min.

Exposure setup

Exposure source	Merritt coils
Setup	1800 mm x 1400 mm x 600 mm plastic chamber placed in the center of the set of Merritt coils

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	60 µT	-	measured	-	± 0.2 µT

Reference articles

Tokalov SV et al. (2003): The heat shock-induced cell cycle arrest is attenuated by weak electromagnetic fields
Junkersdorf B et al. (2000): Electromagnetic fields enhance the stress response at elevated temperatures in the nematode Caenorhabditis elegans

Exposed system:

intact cell/cell culture
HL-60 cells (human acute myeloid leukaemia cell line)

Methods Endpoint/measurement parameters/methodology

molecular biosynthesis: gene expression of the heat shock proteins HSP27, HSP60, HSP70, HSP75, HSP78, HSP90 (RT-PCR)
cell viability/cell division/proliferation: cell cycle distribution (propidium iodide staining, flow cytometry); cell proliferation (staining with carboxyfluorescin succinimyl ester and propidium iodide, flow cytometry)

Investigated system:

DNA/RNA
intact cell/cell culture

Time of investigation:

after exposure

Main outcome of study (acc. to author)

While X-rays and heat shock significantly influenced the cell proliferation and the cell cycle distribution compared to the control group these parameters were not significantly altered in cell cultures exposed to magnetic fields. A combination of magnetic field exposure and heat shock attenuated the heat shock induced effects. However, no such preventing effect was observed in the combination of X-rays and magnetic fields.
Treatment with heat shock, alone and in combination with X-rays and magnetic fields, led to significantly increased protein expression levels of HSP27, HSP70, HSP75 and HSP78 in comparison to the control cell cultures, while the exposure to magnetic fields alone only significantly increased the protein expression of HSP70.
The authors conclude that extremely low frequency magnetic fields can alter the protein expression level of HSP70 in a human leukemia cell line, but have no influence on cell proliferation and cell cycle. Furthermore, a protective effect of the magnetic fields was observed in heat shocked but not in X-radiated cells.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Deutsche Forschungsgemeinschaft (DFG; German Research Foundation)

Koziorowska A et al. (2017): Electromagnetic field of extremely low frequency (60Hz and 120Hz) effects the cell cycle progression and the metabolic activity of the anterior pituitary gland cells in vitro
Jin H et al. (2015): Effects on G2/M phase cell cycle distribution and aneuploidy formation of exposure to a 60 Hz electromagnetic field in combination with ionizing radiation or hydrogen peroxide in L132 nontumorigenic human lung epithelial cells
Huang CY et al. (2014): Distinct Epidermal Keratinocytes Respond to Extremely Low-Frequency Electromagnetic Fields Differently
Huang CY et al. (2014): Extremely Low-Frequency Electromagnetic Fields Cause G1 Phase Arrest through the Activation of the ATM-Chk2-p21 Pathway
Mannerling AC et al. (2010): Effects of 50-Hz magnetic field exposure on superoxide radical anion formation and HSP70 induction in human K562 cells
Garip AI et al. (2010): Effect of ELF-EMF on number of apoptotic cells; correlation with reactive oxygen species and HSP
Bodega G et al. (2005): Acute and chronic effects of exposure to a 1-mT magnetic field on the cytoskeleton, stress proteins, and proliferation of astroglial cells in culture
Lange S et al. (2004): Modifications in cell cycle kinetics and in expression of G1 phase-regulating proteins in human amniotic cells after exposure to electromagnetic fields and ionizing radiation
Tokalov SV et al. (2003): The heat shock-induced cell cycle arrest is attenuated by weak electromagnetic fields
Yoshizawa H et al. (2002): No effect of extremely low-frequency magnetic field observed on cell growth or initial response of cell proliferation in human cancer cell lines
Harris PA et al. (2002): Possible attenuation of the G2 DNA damage cell cycle checkpoint in HeLa cells by extremely low frequency (ELF) electromagnetic fields