Effects of radiofrequency exposure emitted from a GSM mobile phone on proliferation, differentiation, and apoptosis of neural stem cells

Abstract

Due to the importance of neural stem cells (NSCs) in plasticity of the nervous system and treating neurodegenerative diseases, the main goal of this study was to evaluate the effects of radiofrequency radiation emitted from a GSM 900-MHz mobile phone with different exposure duration on proliferation, differentiation and apoptosis of adult murine NSCs in vitro. We used neurosphere assay to evaluate NSCs proliferation, and immunofluorescence assay of neural cell markers to examine NSCs differentiation. We also employed alamarBlue and caspase 3 apoptosis assays to assess harmful effects of mobile phone on NSCs. Our results showed that the number and size of resulting neurospheres and also the percentage of cells differentiated into neurons decreased significantly with increasing exposure duration to GSM 900-MHz radiofrequency (RF)-electromagnetic field (EMF). In contrast, exposure to GSM 900-MHz RF-EMF at different durations did not influence cell viability and apoptosis of NSCs and also their astrocytic differentiation. It is concluded that accumulating dose of GSM 900-MHz RF-EMF might have devastating effects on NSCs proliferation and neurogenesis requiring more causations in terms of using mobile devices.

Keywords: Apoptosis; Cell differentiation; Cell phones; Cell proliferation; Electromagnetic fields; Microwaves; Neural stem cells; Radiofrequency.

Fig. 1. Effect of GSM 900 MHz on proliferation of adult neural stem cells in vitro. (A) Mean neurosphere forming frequency. (B) Mean neurosphere diameter. (C) Representative neurospheres formed in different treatment groups. Scale bar=100 µm. ^**P<.01, ^***P<0.001.

Fig. 2. Effect of GSM 900 MHz on differentiation of neural stem cell. (A) Mean percentage of astrocytes. (B) Mean percentage of neurons. (C) Representative immunostained pictures from the control and 120-minute treatment groups. GFAP, glial fibrillary acidic protein; IR, immunoreactive. Scale bar=100 µm. ^*P<0.05, ^***P<0.001.

Fig. 3. Effect of GSM 900 MHz on cell viability and apoptosis. (A) Cell viability of neural stem cells using alamarBlue assay. (B) Mean percentage of caspase 3 apoptotic cells in different treatment groups. (C) Representative flow cytometry plot analyzing caspase 3 immunoreactive cells.