Medical/biological study (experimental study)

Spatial learning, monoamines and oxidative stress in rats exposed to 900 MHz electromagnetic field in combination with iron overload med./bio.

By: Maaroufi K, Had-Aissouni L, Melon C, Sakly M, Abdelmelek H, Poucet B, Save E

Published in: Behav Brain Res 2014; 258: 80-89

Aim of study (acc. to author)

To investigate whether co-exposure to electromagnetic fields and iron overload has a greater impact on rat brain tissues than electromagnetic field exposure alone.

Background/further details

Neurodegenerative diseases (e.g. Parkinson's disease or Alzheimer's disease) have been suggested to be linked to electromagnetic fields and iron overload in the brain. Thereby, the combination of both factors could have a greater impact than each treatment for itself.
Three groups of rats were examined (n=8 per group): 1.) electromagnetic field exposure, 2.) electromagnetic field exposure + iron administration (daily injection of 3 mg FeSO₄ per kg body weight during 21 consecutive days) and 3.) sham exposure. After the exposure period of 21 days, behavior tests were performed (post-treatment day 1-8: Morris water maze, post-treatment day 14-20: eight-arm radial maze, post treatment day 21, 22 or 23: object exploration task). At the end of the experimental period, rats were killed for biochemical measurements.

Endpoint

effects on the neurological system: level of dopamine and serotonin, oxidative stress in brain
cognitive/behavioral endpoints: spatial learning and memory

Exposure

- 900 MHz
- mobile communications
- mobile phone
- co-exposure

Exposure	Parameters
Exposure 1: 900 MHz Exposure duration: 1 hour per day for 21 consecutive days	SAR: 0.05 W/kg minimum SAR: 0.18 W/kg maximum power: 100 mW

Exposure 1

Main characteristics

Frequency	900 MHz
Type	electromagnetic field
Exposure duration	1 hour per day for 21 consecutive days

Exposure setup

Exposure source	dipole antenna
Chamber	cage (40 cm x 26 cm x 16 cm) with a plexiglas cover containing 6 rats was placed in the exposure chamber, chamber was formed by absorbent material to limit stray reflections
Setup	apparatus (containing the dipole antenna and the chamber) was placed in a temperature controlled (20°C), dimly lit room (1,7 m x 3.2 m) on a table; antenna was placed at a 50 cm distance to the center of the chamber
Sham exposure	A sham exposure was conducted.

Parameters

Measurand	Value	Type	Method	Mass	Remarks
SAR	0.05 W/kg	minimum	estimated	-	-
SAR	0.18 W/kg	maximum	estimated	-	-
power	100 mW	-	-	-	-

Exposed system:

animal
rat/Long-Evans
whole body

Methods Endpoint/measurement parameters/methodology

effects on the neurological system: levels of dopamine and serotonin and their metabolites (3,4-dihydroxyphenylacetic acid, 5-hydroxyindolacetic acid) in supernatants of brain homogenates (high performance liquid chromatography); oxidative stress in supernatants of brain homogenates: enzyme activity of catalase and superoxide dismutase (commercial kit, spectroscopy), lipid peroxidation (level of malondialdehyde via thiobarbituric acid-reactive substances, spectrophotometry)
cognitive/behavioral endpoints: spatial learning and memory (Morris water maze); working memory (re-entries in arms already visited, eight-arm radial maze); object exploration behavior in open field test with different objects (distance run, time spent by the rat's snout in a circular area around an object (<2 cm), object recognition and spatial memory)

Investigated system:

isolated bio./chem. substance
supernatants of homogenates of brain areas (cerebellum, striatum, hippocampus, prefrontal cortex)
investigation on living organism

Investigated organ system:

brain/CNS

Time of investigation:

after exposure

Main outcome of study (acc. to author)

No significant differences regarding learning and memory were observed in the Morris water maze and eight-arm radial maze between the groups. However, exposed rats from group 1 (electromagnetic field) and group 2 (electromagnetic field + iron) showed significantly impaired results in the object exploration test in comparison to the sham exposed rats.
Rats exposed to an electromagnetic field (group 1) showed significant decreases in the levels of dopamine and serotonin in the hippocampus compared to group 2 and group 3 (sham exposure). The level of serotonin and its metabolite (5-hydroxyindolacetic acid) was significantly increased in the cerebellum in both exposure groups (group 1 and 2) in comparison to the sham exposure group. Additionally, the level of dopamine was significantly increased in the striatum of group 2 compared to group 1 and group 3.
No differences regarding oxidative stress parameters were found between the groups.
The authors conclude that electromagnetic field exposure had an impact on the brain of rats, but no synergistic effects of exposure to an electromagnetic field and iron overload occurred.

Study character:

medical/biological study
experimental study
full/main study

Study funded by

Aix Marseille Université, France
Centre National de la Recherche Scientifique (CNRS; French National Center for Scientific Research), France

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