Exposure to 835 MHz radiofrequency electromagnetic field induces autophagy in hippocampus but not in brain stem of mice

Abstract

The exploding popularity of mobile phones and their close proximity to the brain when in use has raised public concern regarding possible adverse effects from exposure to radiofrequency electromagnetic fields (RF-EMF) on the central nervous system. Numerous studies have suggested that RF-EMF emitted by mobile phones can influence neuronal functions in the brain. Currently, there is still very limited information on what biological mechanisms influence neuronal cells of the brain. In the present study, we explored whether autophagy is triggered in the hippocampus or brain stem after RF-EMF exposure. C57BL/6 mice were exposed to 835 MHz RF-EMF with specific absorption rates (SAR) of 4.0 W/kg for 12 weeks; afterward, the hippocampus and brain stem of mice were dissected and analyzed. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis demonstrated that several autophagic genes, which play key roles in autophagy regulation, were significantly upregulated only in the hippocampus and not in the brain stem. Expression levels of LC3B-II protein and p62, crucial autophagic regulatory proteins, were significantly changed only in the hippocampus. In parallel, transmission electron microscopy (TEM) revealed an increase in the number of autophagosomes and autolysosomes in the hippocampal neurons of RF-EMF-exposed mice. The present study revealed that autophagy was induced in the hippocampus, not in the brain stem, in 835 MHz RF-EMF with an SAR of 4.0 W/kg for 12 weeks. These results could suggest that among the various adaptation processes to the RF-EMF exposure environment, autophagic degradation is one possible mechanism in specific brain regions.

Prenatal and early postnatal exposure to radiofrequency waves (900 MHz) adversely affects passive avoidance learning and memory

“…A deleterious effect of exposure to 900 MHz RFW on learning and memory in adult rats has already been reported (Azimzadeh et al, 2018; Azimzadeh and Jelodar, 2020; Jelodar et al, 2018). Moreover, similar evidence has been reported with different frequencies (835, 900, 1800, and 2100 MHz) in addition to devastating effects on hippocampal morphology (Gokcek-Sarac et al, 2017; Krishna Kishore et al, 2019; Kim et al, 2018; Kivrak et al, 2017). However, exposure to 900 MHz EMF has not adversely affected spatial nor nonspatial memory (Dubreuil et al, 2003; Sienkiewicz et al, 2000; Tan et al, 2017).…”

1800 MHz Radiofrequency Electromagnetic Field Impairs Neurite Outgrowth Through Inhibiting EPHA5 Signaling

“…The potential mechanisms that RF-EMF acts on the brain indicated by previous studies including influencing the normal functions of the blood-brain barrier (Sirav and Seyhan, 2016;Poulletier de Gannes et al, 2017), inducing neuroinflammation (Lameth et al, 2017), altering the activity of specific calcium channels (Buckner et al, 2015), inducing autophagy (Kim et al, 2018b), and stimulating oxidative stress (Tsoy et al, 2019). Previous studies have also indicated that RF-EMF exposure changes the expression of specific genes related to neuronal development (Nikolova et al, 2005;Zhao et al, 2007).…”

Early exposure to radiofrequency electromagnetic fields at 1850 MHz affects auditory circuits in early postnatal mice

“…Additional cellular effects of RF-EMF exposure may involve changes in the regulation of the cell cycle 7,8 and alterations of intracellular and molecular pathways, such as the extracellular signal-regulated kinase pathway 2 . It has also been reported that exposure to RF-EMF can induce changes in the central nerve system, including autophagy 9 , apoptosis 10 , and synaptic trafficking of synaptic vesicles 5 .…”