Medical/biological study (experimental study)

Noise magnetic fields abolish the gap junction intercellular communication suppression induced by 50 Hz magnetic fields med./bio.

By: Zeng Q, Ke X, Gao X, Fu Y, Lu D, Chiang H, Xu Z

Published in: Bioelectromagnetics 2006; 27 (4): 274-279

Aim of study (acc. to author)

To study the effects of noise magnetic field on magnetic field-induced gap junction intercellular communication inhibition.

Background/further details

The study is an extension of previous studies (publication 387, publication 10066). Exposure to a 50 Hz sinusoidal magnetic field for 24 h inhibited gap junction intercellular communication in CHL cells at an intensity of 0.4 mT and enhanced the inhibition effect of TPA at 0.2 mT.
Cell were exposed with or without TPA (5 ng/ml).

Endpoint

cell function: gap junctional intercellular communication inhibition

Exposure

- 50/60 Hz
- magnetic field

Exposure	Parameters
Exposure 1: 50 Hz Exposure duration: continuous for 24 h	magnetic flux density: 0.2 mT effective value magnetic flux density: 0.4 mT effective value

General information

The experiments were conducted in 8 treatment groups with 4 dishes in each group: 1) sham exposure, 2) 0.4 mT MF alone, 3) 0.4 mT MF + 0.4 mT noise MF, 4) 0.4 mT noise alone, 5) 0.2 mT MF plus TPA (5 ng/ml), 6) same as 5 plus noise MF, 7) 0.2 mT alone, 8) 5 ng/ml TPA alone.

Exposure 1

Main characteristics

Frequency	50 Hz
Type	magnetic field
Waveform	sinusoidal
Exposure duration	continuous for 24 h

Exposure setup

Exposure source	coil(s)
Setup	Three groups of square coils (36 x 36 cm) placed in a CO₂ incubator. The upper, middle and the lower coils were connected in series and spaced 8 cm apart from each other. The coils were placed in an iron metal container with a lot ventilation holes to shield cells from stray MF. A very uniform magnetic field was present in the center (10 x 10 x 10 cm³) of the coils, where the cells were located.
Sham exposure	A sham exposure was conducted.
Additional info	To generate noise MF, the coils system was double-wrapped with two lines of copper wires. One of the double wires was provided with 30-910 Hz white noise signal and the other was fed with 50 Hz AC current.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
magnetic flux density	0.2 mT	effective value	measured	-	-
magnetic flux density	0.4 mT	effective value	measured	-	-

Measurement and calculation details

Magnetic field densities were measured with a Model EFA-3 meter.

Reference articles

Zeng QL et al. (2003): ELF magnetic fields induce internalization of gap junction protein connexin 43 in Chinese hamster lung cells

Exposed system:

intact cell/cell culture
NIH3T3 cells (mouse fibroblasts)

Methods Endpoint/measurement parameters/methodology

cell function: gap junctional intercellular communication inhibition (fluorescence recovery after photobleaching (FRAP))

Investigated system:

intact cell/cell culture

Time of investigation:

after exposure

Main outcome of study (acc. to author)

The gap junction intercellular communication of NIH3T3 cells was significantly inhibited by magnetic field exposure. However, there were no significant differences between the sham exposed cells, "magnetic field + noise magnetic field" exposure, and "noise magnetic field exposure", indicating that the superposition of a noise magnetic field alleviated the suppression of gap junction intercellular communication induced by the 50 Hz magnetic field.
In addition, although magnetic field exposure at 0.2 mT synergistically enhanced TPA-induced gap junction intercellular communication inhibition further imposition of a noise magnetic field abolished the synergistic effect of coherent magnetic field.
In conclusion, the present data clearly showed that although noise magnetic field itself had no effect on gap junction intercellular communication of NIH3T3 cells, its superposition onto a coherent sinusoidal magnetic field at the same intensity abolished magnetic field-induced gap junction intercellular communication suppression.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

National Natural Science Foundation (NSFC), China

Percherancier Y et al. (2015): Effects of 50 Hz magnetic fields on gap junctional intercellular communication in NIH3T3 cells
Sun W et al. (2010): Superimposition of an Incoherent Magnetic Field Eliminated the Inhibition of Hormone Secretion Induced by a 50-Hz Magnetic Field in Human Villous Trophoblasts in vitro
Yao K et al. (2008): Electromagnetic noise inhibits radiofrequency radiation-induced DNA damage and reactive oxygen species increase in human lens epithelial cells
Sul AR et al. (2006): Effects of sinusoidal electromagnetic field on structure and function of different kinds of cell lines
Somosy Z et al. (2004): Alteration of tight and adherens junctions on 50-Hz magnetic field exposure in Madin Darby canine kidney (MDCK) cells
Zeng QL et al. (2003): ELF magnetic fields induce internalization of gap junction protein connexin 43 in Chinese hamster lung cells
Yamaguchi DT et al. (2002): Inhibition of gap junction intercellular communication by extremely low-frequency electromagnetic fields in osteoblast-like models is dependent on cell differentiation
Hu GL et al. (2002): Study on gap junctional intercellular communication inhibition by ELF magnetic fields using FRAP method
Ye J et al. (2002): Changes in gap junctional intercellular communication in rabbits lens epithelial cells induced by low power density microwave radiation
Li CM et al. (1999): Effects of 50 Hz magnetic fields on gap junctional intercellular communication
Lin H et al. (1995): Electric and magnetic noise blocks the 60 Hz magnetic field enhancement of steady state c-myc transcript levels in human leukemia cells
Litovitz TA et al. (1994): Temporally incoherent magnetic fields mitigate the response of biological systems to temporally coherent magnetic fields
Litovitz TA et al. (1994): Superimposing spatially coherent electromagnetic noise inhibits field-induced abnormalities in developing chick embryos