Histomorphometric study of thyroid tissue in juvenile rats exposed to 5G electromagnetic fields

Authors: Ramelet M, Ronger L, Al-Salameh A, Pelletier A, Desailloud R, Seewooruttun C

Year: 2025

Category: Endocrinology, Experimental Toxicology

Journal: Annales d'Endocrinologie

DOI: 10.1016/j.ando.2025.101755

URL: https://www.sciencedirect.com/science/article/pii/S0003426625000745

Abstract

Overview

With the rollout of 5G networks, concerns have arisen regarding the potential impact of electromagnetic fields (EMF) on health. Previous studies have indicated that EMFs can influence thermal regulation, with rats exposed to 900MHz showing vasoconstriction and a behavioral preference for warmer areas. The hypothalamo-pituitary-thyroid axis, critical for thermogenesis, becomes more active in response to cold, increasing thyroid gland activity and heat production.

Objective

The study aimed to specifically assess thyroid function and activity following exposure to 5G EMF.

Method

  • Ten 3-week-old male Wistar rats were divided into two groups: 5 rats received 2 weeks of 5G exposure at 3.5GHz and 1.5V/m, while 5 served as controls without exposure.
  • Post-sacrifice, thyroid glands were examined for histomorphometric parameters—measuring follicle and colloid areas along with the Thyroid Activation Index (TAI), defined as the ratio of follicle to colloid area.

Findings

  • Rats exposed to 5G showed significantly larger thyroid follicle and colloid areas compared to controls (2729 μm² vs 2444 μm², P=0.0063; 1317 μm² vs 1015 μm², P=0.0027).
  • The TAI was significantly lower in exposed rats (5.62 vs 7.07, P<0.001), indicating thyroid hypoactivity.

These results implicate that 5G exposure potentially suppresses thyroid activity, with mechanisms differing from standard cold responses.

Conclusion

The study demonstrated a notable impact of 5G EMFs on thyroid function in juvenile rats, suggesting a mechanism of thyroid hypoactivity unrelated to thermal cold response. While these findings highlight an EMF health risk, further research with hormone assays and mechanistic exploration is needed to confirm and elaborate on these concerns.

5G electromagnetic fields thyroid rats histomorphometry endocrine disruption EMF safety
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