Study type: Medical/biological study (experimental study)

Bone morphogenetic protein expression in newborn rat kidneys after prenatal exposure to radiofrequency radiation. med./bio.

Published in: Bioelectromagnetics 2004; 25 (3): 216-227

Aim of study (acc. to author)

A simulation model was designed for the athermal exposure of pregnant rats to pulsed GSM-like radiofrequency radiation (9.4 GHz). Relative expression and localization of bone morphogenetic proteins (BMP) and their receptors (BMPR) were examined in kidneys of rat newborns exposed (sham-exposed) during prenatal development.

Background/further details

BMP and BMPR are members of a molecular family currently considered as major endocrine and autocrine morphogenes and known to be involved in renal development.

Endpoint

Exposure

Exposure Parameters
Exposure 1: 9.4 GHz
Modulation type: pulsed
Exposure duration: continuous during days 1-3 postcoitum
  • power density: 5 µW/cm² unspecified
  • SAR: 500 nW/g maximum (cf. remarks) (calulated by means of numerical method using Finite Elements.)
Exposure 2: 9.4 GHz
Modulation type: pulsed
Exposure duration: continuous during days 4-7 postcoitum
  • SAR: 500 nW/g maximum (cf. remarks) (calculated by means of numerical method using Finite Elements)
  • power density: 5 µW/cm² unspecified

Exposure 1

Main characteristics
Frequency 9.4 GHz
Exposure duration continuous during days 1-3 postcoitum
Modulation
Modulation type pulsed
Pulse width 20 µs
Repetition frequency 50 Hz
Exposure setup
Exposure source
  • 27 cm horn-fed parabolic antennas placed 10 m apart, facing each other.
Distance between exposed object and exposure source 5 m
Chamber Plastic cages /50 cm x 40 cm x 25 cm
Setup 6 cages with four free moving rats per cage were positioned in two horizontal rows by three vertical columns in the middle of the two antennas.
Parameters
Measurand Value Type Method Mass Remarks
power density 5 µW/cm² unspecified measured - -
SAR 500 nW/g maximum calculated cf. remarks calulated by means of numerical method using Finite Elements.

Exposure 2

Main characteristics
Frequency 9.4 GHz
Exposure duration continuous during days 4-7 postcoitum
Modulation
Modulation type pulsed
Pulse width 20 µs
Repetition frequency 50 Hz
Exposure setup
Exposure source
Distance between exposed object and exposure source 5 m
Parameters
Measurand Value Type Method Mass Remarks
SAR 500 nW/g maximum calculated cf. remarks calculated by means of numerical method using Finite Elements
power density 5 µW/cm² unspecified measured - -

Exposed system:

Methods Endpoint/measurement parameters/methodology

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

Main outcome of study (acc. to author)

No malformations were found in the newborns which were exposed to radiofrequency irradiation. At the histological level, kidney sections of irradiated newborn rats occasionally exhibited slight swelling in the tubular cells when compared to corresponding material from sham-exposed rats. Semiquantitative duplex RT-PCR for BMP-4, -7, BMPR-IA, -IB, and -II showed increased BMP-4 and BMPR-IA, and decreased BMPR-II relative expression in kidneys of rat newborns. These changes were statistically significant for BMP-4, BMPR-IA, and -II after irradiation on days 1-3 postcoitum, and for BMP-4 and BMPR-IA after exposure on days 4-7 postcoitum. Immunohistochemistry and in situ hybridization showed aberrant expression and localization of these molecules at the histological level.
The data suggest that GSM-like radiofrequency radiation interferes with gene expression during early gestation and results in aberrations of BMP expression in the newborn animal. These molecular alterations do not appear to affect renal organogenesis and may reflect a delay in the development of this organ. The differences of relative BMP expression after different exposure times indicate the importance of timing for GSM-like radiofrequency radiation effects on embryonic development.

Study character:

Study funded by

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