Medical/biological study (experimental study)

Effect of high-frequency electromagnetic fields on trophoblastic connexins med./bio.

By: Cervellati F, Franceschetti G, Lunghi L, Franzellitti S, Valbonesi P, Fabbri E, Biondi C, Vesce F

Published in: Reprod Toxicol 2009; 28 (1): 59-65

Aim of study (acc. to author)

To study the effects of radiofrequency electromagnetic fields on connexin gene expression and protein expression, as well as connexin localization and ultrastructural cell features in gestational tissue (trophoblast cell line).

Background/further details

Connexins are membrane proteins that are able to influence the trophoblast functions.

Endpoint

molecular biosynthesis: connexin gene expression and protein expression
morphol./histopathol. changes: protein localization and cell ultrastructure

Exposure

- PW pulsed wave
- mobile communications
- digital mobile phone
- GSM

Exposure	Parameters
Exposure 1: 1,817 MHz Modulation type: pulsed Exposure duration: continuous for 1 h	SAR: 2 W/kg average over time

Exposure 1

Main characteristics

Frequency	1,817 MHz
Type	electromagnetic field
Waveform	sinusoidal
Exposure duration	continuous for 1 h

Modulation

Modulation type	pulsed
Repetition frequency	217 Hz
Pulse type	rectangular

Exposure setup

Exposure source	waveguide
Setup	two 128.5 mm x 65 mm x 424 mm brass single mode waveguide resonators; petri dishes kept on plastic holders inside the resonators at the H-field maximum of the standing wave
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	2 W/kg	average over time	measured	-	-

Reference articles

Valbonesi P et al. (2008): Evaluation of HSP70 expression and DNA damage in cells of a human trophoblast cell line exposed to 1.8 GHz amplitude-modulated radiofrequency fields
Schuderer J et al. (2004): High Peak SAR Exposure Unit With Tight Exposure and Environmental Control for In Vitro Experiments at 1800 MHz

Exposed system:

intact cell/cell culture
HTR-8/SVneo (human trophoblast cell line)

Methods Endpoint/measurement parameters/methodology

molecular biosynthesis: connexin gene expression (all connexin genes, e.g. connexin 43, connexin 40, connexin 32, connexin 37; semiquantitative RT-PCR) and protein expression (Western blot)
cell function: responsiveness of adenylyl cyclase to receptorial and non-receptorial agents (e.g. prostaglandin, epinephrine) (intracellular cAMP level)
cell viability/cell division/proliferation: cell viability (MTT assay)
morphol./histopathol. changes: protein localization (immunofluorescence) and cell ultrastructure (toluidine blue stain; electron microscopy)

Investigated system:

isolated bio./chem. substance
DNA/RNA
intact cell/cell culture
tissue slices
cell supernatants

Time of investigation:

after exposure

Main outcome of study (acc. to author)

Radiofrequency exposure significantly and selectively increased gene expression of connexin 40 and connexin 43, without altering protein expression. Nevertheless, connexin 40 and connexin 43 lost their punctate fluorescence within the cell membrane (compared to sham exposed cells), becoming diffuse after exposure. Thus, localization of connexin 40 and connexin 43 was significantly changed following exposure. Electron microscopy evidenced a sharp decrease in intercellular gap junction-like structures. Cell viability and cell functionality were not significantly influenced by electromagnetic field exposure.
The data indicate that exposure of extravillous trophoblast to GSM-217 Hz signals can modify connexin gene expression, connexin protein localization and cellular ultrastructure.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Fondazione Cassa di Risparmio di Cento, Italy
University of Ferrara, Italy

Cervellati F et al. (2013): 17-β-Estradiol counteracts the effects of high frequency electromagnetic fields on trophoblastic connexins and integrins
Valbonesi P et al. (2008): Evaluation of HSP70 expression and DNA damage in cells of a human trophoblast cell line exposed to 1.8 GHz amplitude-modulated radiofrequency fields
Franzellitti S et al. (2008): HSP70 expression in human trophoblast cells exposed to different 1.8 Ghz mobile phone signals
Sul AR et al. (2006): Effects of sinusoidal electromagnetic field on structure and function of different kinds of cell lines
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
Ye J et al. (2002): Changes in gap junctional intercellular communication in rabbits lens epithelial cells induced by low power density microwave radiation