Possible effects of RF EMR on contextual fear conditioning, hippocampal perivascular space, apoptosis and adrenal gland microarchitecture in rats

Authors: Narayanan SN, Kumar RS, Kumar N, Prabhakar P, Nayak SB, Bhat PG

Year: 2025 Mar 12

Category: Neuroscience

Journal: Behavioural Brain Research

DOI: 10.1016/j.bbr.2025.115424

URL: https://www.sciencedirect.com/science/article/pii/S0166432825000105?via%3Dihub

Abstract

Overview

As mobile phone technology rapidly expands worldwide, concerns over the possible health effects induced by radiofrequency electromagnetic radiation (RF-EMR) have intensified. This study investigates the hypothesis that chronic 900 MHz RF-EMR exposure could dysregulate the stress response system (specifically the HPA axis) via non-thermal mechanisms. The study explores potential alterations in the microarchitecture of the adrenal gland and vulnerability in brain regions such as the hippocampus, which may lead to altered behaviors in rats.

Methods

  • Male albino Wistar rats (aged four weeks, 50-60g) were exposed to 900 MHz radiation from a mobile phone for one hour daily over four weeks.
  • On day 29, control, sham exposed, and RF-EMR exposed rats underwent contextual fear conditioning tests.
  • After behavioral testing, rats were euthanized for examination of hippocampal and adrenal gland cytoarchitecture.

Findings

  • RF-EMR exposed rats demonstrated significantly elevated transitions between bright and dark compartments in the avoidance box, and decreased latency to enter the dark compartment.
  • Marked apoptosis was observed in the CA3 region, and the perivascular space in the hippocampus was significantly enlarged in the exposed group.
  • The zona fasciculata of the adrenal gland displayed apoptotic-like changes, lymphocytic infiltrates, and congested sinusoids in the RF-EMR exposed group.
  • The cytoarchitecture of the adrenal medulla remained comparable across all groups.

Conclusion

Chronic exposure to RF-EMR at 900 MHz resulted in:

  • Changes in contextual fear conditioning behavior.
  • Enlargement of hippocampal perivascular space and induction of apoptosis in the CA3 region.
  • Apoptotic and inflammatory changes in the zona fasciculata of the adrenal gland.

These findings indicate a clear association between chronic RF-EMR exposure and adverse neurobehavioral as well as histological changes, reinforcing the link between electromagnetic fields and health risks.

RF-EMR hippocampus adrenal gland apoptosis contextual fear conditioning perivascular space mobile phone radiation
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