5G Radiofrequency Exposure Reduces PRDM16 and C/EBP β mRNA Expression, Two Key Biomarkers for Brown Adipogenesis.

Although 5G technology offers remarkable speed improvements, concerns about its long-term health effects remain. Brown adipose tissue (BAT) is essential for generating heat in mammals, particularly in children, where it is most prevalent. It naturally declines with age. Moreover, children absorb a higher proportion of radiofrequency energy than adults, making them more susceptible to the potential effects of radiofrequency electromagnetic fields (RF-EMF). Previous animal studies have shown that low-intensity RF-EMF can stimulate cold-defense responses, such as vasoconstriction and altered norepinephrine levels. Two primary mechanisms underpin cold-induced brown adipose tissue (BAT) activation: UCP1-dependent thermogenesis and brown adipocyte hyperplasia. This study explores how 2G and 5G exposure impacts genes central to BAT thermogenesis and adipogenesis in juvenile versus young adult rats. The aim is to clarify the age- and duration-dependent impacts and potential metabolic risks.

Sixty male Wistar rats, aged either 3 weeks (juvenile) or 8 weeks (young adult), were divided into three groups: a sham-exposed control group and two exposure groups (2G at 900 MHz and 5G at 3.5 GHz). Each group (n = 5) underwent either one or two weeks of exposure. The animals were exposed twice daily for one hour at 1.5 V/m, corresponding to whole-body SAR values of 0.07 mW/kg (5G) and 0.24 mW/kg (2G). After exposure, the interscapular BAT was collected and analyzed by quantitative PCR to determine the mRNA levels of thermogenic markers (UCP1, UCP3, PGC1α, PPARα, PPARγ, Cidea, ADRß3, S100b) and adipogenic markers (PRDM16, C/EBP β, C/EBP α, Zfp423).

5G exposure induced a significant downregulation of adipogenic transcription factors PRDM16 (-49%), C/EBP β (-32%), and Zfp423 (-30%), regardless of age and exposure duration. In contrast, 2G exposure produced an age-dependent decrease in PPARα only in young adult rats. ADRß3 expression increased under both 2G and 5G conditions in a duration-dependent manner: juvenile rats exhibited a significant increase only after one week of exposure.

The authors conclude that 5G radiofrequency exposure may impair brown adipocyte differentiation by downregulating PRDM16, C/EBP β, and Zfp423, thereby reducing BAT-mediated heat production and increasing cold sensitivity. The core UCP1 thermogenic pathway appears unaffected by RF-EMF. Alterations in PPARα and ADRβ3 suggest exposure- and age-specific effects of RF-EMF on brown fat biology.

Editor's note:

The extremely low field strengths and SAR values at which non-thermal effects occur are alarming. ICNIRP limits for the general public allow up to 0.08 W/kg, which is roughly a thousand times higher than the 0.07 mW/kg used for 5G in this study. The lack of frequency modulation in the experimental fields suggests that real-world 5G signals could have an even greater biological impact (Lai & Levitt, 2022). Study limitations include small group sizes (n = 5) and the absence of proteomic validation –mRNA changes may not translate to altered protein levels. Intriguingly, low-intensity radiofrequency electromagnetic fields (RF-EMF) may indeed disrupt mammalian thermoregulation. (RH)

Lai H, Levitt BB. (2022). The roles of intensity, exposure duration, and modulation on the biological effects of radiofrequency radiation and exposure guidelines. In Electromagnetic Biology and Medicine (Vol. 41, Issue 2, pp. 230–255). Taylor & Francis. https://doi.org/10.1080/15368378.2022.2065683