Fibroblast cells will be exposed to 900 MHz (GSM) and analyzed for DNA strand breaks using standard Comet and Pulse Field Gel Electrophoresis. In addition, immunological and chromatographic techniques will be used to examine the type and amount of DNA damage generated. Western blotting, immunofluorescence microscopy, and flow cytometry will be used to examine any cellular DNA damage response. Microarray technology (Affymetrics, GeneChips) will be used to monitor changes in gene expression profiles. The nature of any molecular or cytogenetic mechanisms providing resistance to RF will also be analyzed. The study is specifically designed to address previous reports from the REFLEX program of genotoxic effects due to non-thermal RF exposure.
AUTHORS'S ABSTRACT: Xu et al. 2013 (IEEE #5256):
BACKGROUND: Although IARC clarifies radiofrequency electromagnetic fields (RF-EMF) as possible human carcinogen, the debate on its health impact continues due to the inconsistent results. Genotoxic effect has been considered as a golden standard to determine if an environmental factor is a carcinogen, but the currently available data for RF-EMF remain controversial. As an environmental stimulus, the effect of RF-EMF on cellular DNA may be subtle. Therefore, more sensitive method and systematic research strategy are warranted to evaluate its genotoxicity.
OBJECTIVES: To determine whether RF-EMF does induce DNA damage and if the effect is cell-type dependent by adopting a more sensitive method ³H2AX foci formation; and to investigate the biological consequences if RF-EMF does increase ³H2AX foci formation.
METHODS: Six different types of cells were intermittently exposed to GSM 1800 MHz RF-EMF at a specific absorption rate of 3.0 W/kg for 1 h or 24 h, then subjected to immunostaining with anti-³H2AX antibody. The biological consequences in ³H2AX-elevated cell type were further explored with comet and TUNEL assays, flow cytometry, and cell growth assay.
RESULTS: Exposure to RF-EMF for 24 h significantly induced ³H2AX foci formation in Chinese hamster lung cells and Human skin fibroblasts (HSFs), but not the other cells. However, RF-EMF-elevated ³H2AX foci formation in HSF cells did not result in detectable DNA fragmentation, sustainable cell cycle arrest, cell proliferation or viability change. RF-EMF exposure slightly but not significantly increased the cellular ROS level.
CONCLUSIONS: RF-EMF induces DNA damage in a cell type-dependent manner, but the elevated ³H2AX foci formation in HSF cells does not result in significant cellular dysfunctions.