Bone morphogenetic protein expression in newborn rat kidneys after prenatal exposure to radiofrequency radiation

Authors

  • Athina Pyrpasopoulou,

    1. Laboratory of Pathology, Department of Medicine, School of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
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  • Vassiliki Kotoula,

    1. Laboratory of Pathology, Department of Medicine, School of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
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  • Angeliki Cheva,

    1. Laboratory of Pathology, Department of Medicine, School of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
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  • Prodromos Hytiroglou,

    1. Laboratory of Pathology, Department of Medicine, School of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
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  • Eleni Nikolakaki,

    1. Laboratory of Biochemistry, Department of Chemistry, School of Natural Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
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  • Ioannis N. Magras,

    1. Laboratory of Anatomy, Histology and Embryology, Department of Veterinary Medicine, School of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
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  • Thomas D. Xenos,

    1. Department of Electrical and Computer Engineering, School of Engineering, Aristotle University of Thessaloniki, Thessaloniki, Greece
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  • Theodoros D. Tsiboukis,

    1. Department of Electrical and Computer Engineering, School of Engineering, Aristotle University of Thessaloniki, Thessaloniki, Greece
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  • Georgios Karkavelas

    Corresponding author
    1. Laboratory of Pathology, Department of Medicine, School of Health Sciences, Aristotle University of Thessaloniki, Thessaloniki, Greece
    • Laboratory of Pathology, Department of Medicine, School of Health Sciences, Aristotle University of Thessaloniki, 54006 Thessaloniki, Greece.
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  • A. Pyrpasopoulou and V. Kotoula contributed equally to this work.

Abstract

Effects of nonthermal radiofrequency radiation (RFR) of the global system of mobile communication (GSM) cellular phones have been as yet mostly studied at the molecular level in the context of cellular stress and proliferation, as well as neurotransmitter production and localization. In this study, a simulation model was designed for the exposure of pregnant rats to pulsed GSM-like RFR (9.4 GHz), based on the different resonant frequencies of man and rat. The power density applied was 5 μW/cm2, in order to avoid thermal electromagnetic effects as much as possible. Pregnant rats were exposed to RFR during days 1–3 postcoitum (p.c.) (embryogenesis, pre-implantation) and days 4–7 p.c. (early organogenesis, peri-implantation). Relative expression and localization of bone morphogenetic proteins (BMP) and their receptors (BMPR), members of a molecular family currently considered as major endocrine and autocrine morphogens and known to be involved in renal development, were investigated in newborn kidneys from RFR exposed and sham irradiated (control) rats. Semi-quantitative 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 newborn kidneys. These changes were statistically significant for BMP-4, BMPR-IA, and -II after exposure on days 1–3 p.c. (P < .001 each), and for BMP-4 and BMPR-IA after exposure on days 4–7 p.c. (P < .001 and P = .005, respectively). Immunohistochemistry and in situ hybridization (ISH) showed aberrant expression and localization of these molecules at the histological level. Our findings suggest that GSM-like RFR interferes with gene expression during early gestation and results in aberrations of BMP expression in the newborn. These molecular changes 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 time periods of exposure indicate the importance of timing for GSM-like RFR effects on embryonic development. Bioelectromagnetics 25:216–227, 2004. © 2004 Wiley-Liss, Inc.

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