Study type: Medical/biological study (experimental study)

Effect of an acute 900MHz GSM exposure on glia in the rat brain: a time-dependent study. med./bio.

Published in: Toxicology 2007; 238 (1): 23-33

Aim of study (acc. to author)

This in vivo study was performed to reproduce and complete the result of publication 6611 which found an astrocytes activation (glial reaction) in the rat brain after a single 15 min GSM exposure.

Background/further details

Several brain regions (frontal cortex, striatum, globus pallidus, hippocampus, cortex of cerebellum) were examined in their glial fibrillary acidic protein (GFAP) level as it is a well-established marker to study astrocytes activation.
48 male rats (six weeks old, weighting 220-250 g) were divided into four exposure groups nine animals each and two sham exposure groups six animals each.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 900 MHz
Modulation type: pulsed
Exposure duration: continuous for 15 min
  • SAR: 6 W/kg average over mass (brain) (±20%)

Exposure 1

Main characteristics
Frequency 900 MHz
Type
Exposure duration continuous for 15 min
Modulation
Modulation type pulsed
Duty cycle 12.5 %
Repetition frequency 217 Hz
Additional info

GSM

Exposure setup
Exposure source
Chamber The exposure setup has been described in [Dubreuil et al., 2002; Mausset et al., 2001]. Rats were restrained in individual 5-mm thick perforated Plexiglas tubes, 6 cm in diameter and 15 cm long, with an open-ended cone (3 cm long) in which the rat head was inserted. Animals could rotate their heads but its longitudinal position was fixed.
Setup An RF generator was connected to a four-output divider, allowing simultaneous exposure of four animals. Each output was connected to a loop antenna that was placed against the cone directly above the rat's head for local exposure. A Luxtron optical temperature probe was fixed on the skin of the rat's head below the antenna.
Sham exposure A sham exposure was conducted.
Additional info RF and sham exposed animals were placed at the same time in separate anechoic chambers. Two additional control groups were included: a negative cage control group without any manipulation and an immunostaining positive control group, 4 h after an i.v. injection of LipoPolySaccharide (LPS) solution in saline.
Parameters
Measurand Value Type Method Mass Remarks
SAR 6 W/kg average over mass calculated brain ±20%

Reference articles

Exposed system:

Methods Endpoint/measurement parameters/methodology

Investigated system:
Investigated organ system:
Time of investigation:
  • after exposure

Main outcome of study (acc. to author)

Two days after the 900 MHz GSM exposure a statistically significant increase of GFAP stained area was observed in the frontal cortex and the striatum. A smaller statistically significant increase was found three days after exposure in the same areas and in the cerebellum cortex. These increased GFAP levels indicating astrocytes activation were transient.
The data confirm the result of publication 6611 concerning glial reaction in specific brain regions. Whether this effect could be harmful should be investigated in further studies.

Study character:

Study funded by

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