ID Number		2484
Study Type		In Vitro
Model		Spiral ganglion neurons exposed in vitro to 1800 MHz (GSM) signals at 2 and 4 W/kg for 24 h (5 min on; 10 off).
Details		AUTHORS' ABSTRACT: Zuo et al. 2015 (IEEE #5989): Background: With the increasing popularity of mobile phones, the potential hazards of radiofrequency electromagnetic radiation (RF-EMR) on the auditory system remain unclear. Apart from RF-EMR, humans are also exposed to various physical and chemical factors. We established a lipopolysaccharide (LPS)-induced inflammation in vitro model to investigate whether the possible sensitivity of spiral ganglion neurons to damage caused by mobile phone electromagnetic radiation (at specific absorption rates: 2, 4 W/kg) will increase. Methods: Spiral ganglion neurons (SGN) were obtained from neonatal (1- to 3-day-old) Sprague Dawley® (SD) rats. After the SGN were treated with different concentrations (0, 20, 40, 50, 100, 200, and 400 ¼g/ml) of LPS, the Cell Counting Kit-8 (CCK-8) and alkaline comet assay were used to quantify cellular activity and DNA damage, respectively. The SGN were treated with the moderate LPS concentrations before RF-EMR exposure. After 24 h intermittent exposure at an absorption rate of 2 and 4 W/kg, DNA damage was examined by alkaline comet assay, ultrastructure changes were detected by transmission electron microscopy, and expression of the autophagy markers LC3-II and Beclin1 were examined by immunofluorescence and confocal laser scanning microscopy. Reactive oxygen species (ROS) production was quantified by the chlorofluorescin-diacetate assay. Results: LPS (100 ¼g/ml) induced DNA damage and suppressed cellular activity (P < 0.05). LPS (40 ¼g/ml) did not exhibit cellular activity changes or DNA damage (P > 0.05); therefore, 40 ¼g/ml was used to pretreat the concentration before exposure to RF-EMR. RF-EMR could not directly induce DNA damage. However, the 4 W/kg combined with LPS (40 ¼g/ml) group showed mitochondria vacuoles, karyopyknosis, presence of lysosomes and autophagosome, and increasing expression of LC3-II and Beclin1. The ROS values significantly increased in the 4 W/kg exposure, 4 W/kg combined with LPS (40 ¼g/ml) exposure, and H2O2 groups (P < 0.05, 0.01). Conclusions: Short-term exposure to radiofrequency electromagnetic radiation could not directly induce DNA damage in normal spiral ganglion neurons, but it could cause the changes of cellular ultrastructure at special SAR 4.0 W/kg when cells are in fragile or micro-damaged condition. It seems that the sensitivity of SGN to damage caused by mobile phone electromagnetic radiation will increase in a lipopolysaccharide-induced inflammation in vitro model.
Findings		Effects
Status		Completed With Publication
Principal Investigator		Huazhong U of Science and Tech, Wuhan, China
Funding Agency		?????
Country		CHINA
References		Zuo, WQ et al. Journal of Neuroinflammation, (2015) 12:105-(13 pages)
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