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Possible cause for altered spatial cognition of prepubescent rats exposed to chronic radiofrequency electromagnetic radiation

Abstract

The effects of chronic and repeated radiofrequency electromagnetic radiation (RFEMR) exposure on spatial cognition and hippocampal architecture were investigated in prepubescent rats. Four weeks old male Wistar rats were exposed to RF-EMR (900 MHz; SAR-1.15 W/kg with peak power density of 146.60 μW/cm2) for 1 h/day, for 28 days. Followed by this, spatial cognition was evaluated by Morris water maze test. To evaluate the hippocampal morphology; H&E staining, cresyl violet staining, and Golgi-Cox staining were performed on hippocampal sections. CA3 pyramidal neuron morphology and surviving neuron count (in CA3 region) were studied using H&E and cresyl violet stained sections. Dendritic arborization pattern of CA3 pyramidal neuron was investigated by concentric circle method. Progressive learning abilities were found to be decreased in RF-EMR exposed rats. Memory retention test performed 24 h after the last training revealed minor spatial memory deficit in RF-EMR exposed group. However, RF-EMR exposed rats exhibited poor spatial memory retention when tested 48 h after the final trial. Hirano bodies and Granulovacuolar bodies were absent in the CA3 pyramidal neurons of different groups studied. Nevertheless, RF-EMR exposure affected the viable cell count in dorsal hippocampal CA3 region. RF-EMR exposure influenced dendritic arborization pattern of both apical and basal dendritic trees in RF-EMR exposed rats. Structural changes found in the hippocampus of RF-EMR exposed rats could be one of the possible reasons for altered cognition.

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Acknowledgments

The excellent technical expertise received from Dr. Vasavi Rakesh Gorantla, Assistant Professor and Mr. Raghu Jetty, Senior Grade Lecturer, Department of Anatomy, Melaka Manipal Medical College (Manipal Campus), Manipal University, in brain histology procedures is gratefully acknowledged. Authors also thank Dr. Binu V. S., Associate Professor, Department of Statistics, Manipal University, for his valuable suggestions in statistical analysis. We wish to thank Dr. K. N. Maruthy, Professor, Department of Physiology, Narayana Medical College, Nellore, for designing and fabricating the auto dialer unit for the study. The authors would like to thank Indian Council of Medical Research (ICMR), New Delhi, for partly funding (No. 5/10/FR/21/2011-RHN, IRIS ID: 2011-08800) this research work.

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Funding

This study was partly funded by Indian Council of Medical Research (ICMR), New Delhi (Grant No. 5/10/FR/21/2011-RHN, IRIS ID: 2011-08800).

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The authors declare that they have no conflict of interest.

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All applicable international, national, and/or institutional guidelines for the care and use of animals were followed.

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Correspondence to Sareesh Naduvil Narayanan.

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Narayanan, S.N., Kumar, R.S., Karun, K.M. et al. Possible cause for altered spatial cognition of prepubescent rats exposed to chronic radiofrequency electromagnetic radiation. Metab Brain Dis 30, 1193–1206 (2015). https://doi.org/10.1007/s11011-015-9689-6

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  • DOI: https://doi.org/10.1007/s11011-015-9689-6

Keywords

  • Mobile phone
  • Cognition
  • Prepubescent rat
  • Hippocampus
  • Morris water maze