Medical/biological study (experimental study)

GSM-900MHz at low dose temperature-dependently downregulates alpha-synuclein in cultured cerebral cells independently of chaperone-mediated-autophagy med./bio.

By: Terro F, Magnaudeix A, Crochetet M, Martin L, Bourthoumieu S, Wilson CM, Yardin C, Leveque P

Published in: Toxicology 2012; 292 (2-3): 136-144

Aim of study (acc. to author)

To examine the effects of chronic exposure to low GSM-900 MHz on apoptosis and chaperone-mediated auto-phagocytosis.

Background/further details

Apoptosis was analysed and the expression of proteins involved in chaperone-mediated auto-phagocytosis (cellfunction, that allows protein degradation in the lysosomes, increases under stress conditions) as well as the level of alpha-synuclein (substrate for chaperone-mediated autophagy).
Four types of controls were performed:
1.) controls reproducing exposition-induced temperature elevation at 37.5 °C
2.) heat shock for 30 minutes at 45 °C
3.) negative control (DMSO) and positive control (staurosporin) for apoptosis
4.) positive control for chaperone-mediated auto-phagocytosis (serum deprivation)

Endpoint

cell function: chaperone-mediated auto-phagocytosis
cell viability/cell division/proliferation: apoptosis

Exposure

- 900 MHz
- PW pulsed wave
- mobile communications
- GSM

Exposure	Parameters
Exposure 1: 900 MHz Modulation type: pulsed Exposure duration: continuous for 24 h	SAR: 0.25 W/kg mean

Exposure 1

Main characteristics

Frequency	900 MHz
Type	electromagnetic field
Exposure duration	continuous for 24 h

Modulation

Modulation type	pulsed
Pulse width	0.577 ms
Repetition frequency	217 Hz

Exposure setup

Exposure source	wire-patch cell
Setup	wire-patch cell placed in a chamber with RF-absorbing walls made of ferrite plates; two identical chambers positioned in an incubator one for exposure and one for sham exposure; eight 35 mm petri dishes placed inside a wire-patch cell
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	0.25 W/kg	mean	calculated	-	-

Additional parameter details

additional experiments were performed at 0.5, 1, 2 and 4 W/kg, especially to study the temperature changes during exposure

Reference articles

Bourthoumieu S et al. (2010): Cytogenetic Studies in Human Cells Exposed In Vitro to GSM-900 MHz Radiofrequency Radiation Using R-Banded Karyotyping

Exposed system:

intact cell/cell culture
primary cerebral cortical cells (neurons and astrocytes) of rat embryos

Methods Endpoint/measurement parameters/methodology

molecular biosynthesis: protein expression of Hsp70, Hsc70, Hsp40, Hsp90, Lamp-2A and alpha-synuclein (Western blot); studied also at 2 W/kg
cell function: chaperone-mediated auto-phagocytosis activity (in situ analysis of localisation of active lysosomes in the cell, immunofluorescence staining, fluorescence microscopy)
cell viability/cell division/proliferation: apoptosis (DAPI-stain of nuclei and Western blot of cleaved caspase-3)
morphol./histopathol. changes: cell morphology (chromatin condensation and fragmentation, phase contrast microscopy)

Investigated system:

isolated bio./chem. substance
intact cell/cell culture

Time of investigation:

after exposure

Main outcome of study (acc. to author)

The exposure to GSM-900 MHz failed to induce apoptotic cell death.
The level of Hsc70 was significantly increased after exposure to GSM-900 MHz in comparison to sham exposure, while the level of Hsp90 was significantly decreased, but also in the control group 1 (temperature rise to 37.5 °C). The levels of Lamp-2A, Hsp70 and Hsp40 remained unaltered.
Additionally, the level of alpha-synuclein was significantly decreased after exposure in comparison to sham exposed cells, but also in the control group 1.
The authors suggest that the observed changes in protein expression are most likely linked to temperature rise.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Fondation Santé et Radiofréquences, France

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