The effects of 50 Hz magnetic field exposure on DNA damage and cellular functions in various neurogenic cells

Abstract

Epidemiological studies have indicated a possible association between extremely low–frequency magnetic field (ELF-MF) exposure and the risk of nervous system diseases. However, laboratory studies have not provided consistent results for clarifying this association, despite many years of studies. In this study, we have systematically investigated the effects of 50 Hz MF exposure on DNA damage and cellular functions in both neurogenic tumor cell lines (U251, A172, SH-SY5Y) and primary cultured neurogenic cells from rats (astrocytes, microglia, cortical neurons). The results showed that exposure to a 50 Hz MF at 2.0 mT for up to 24 h did not influence γH2AX foci formation (an early marker of DNA double-strand breaks) in any of six different neurogenic cells. Exposure to a 50 Hz MF did not affect cell cycle progression, cell proliferation or cell viability in neurogenic tumor U251, A172 or SH-SY5Y cells. Furthermore, the MF exposure for 24 h did not significantly affect the secretion of cytokines (TNF-α, IL-6 or IL-1β) in astrocytes or microglia, or the phagocytic activity of microglia. In addition, MF exposure for 1 h per day did not significantly influence expression levels of microtubule-associated protein tau, microtubule-associated protein 2, postsynaptic density 95 or gephyrin in cortical neurons, indicating an absence of effects of MF exposure on the development of cortical neurons. In conclusion, our data suggest that exposure to a 50 Hz MF at 2.0 mT did not elicit DNA damage effects or abnormal cellular functions in the neurogenic cells studied.

30 Hz, Could It Be Part of a Window Frequency for Cellular Response?

“…Nevertheless, based on the hint that the cellular response was dependent on the cell type, prior to starting our experiments, we reviewed the state of the art of specific studies performed with glioblastoma cells models [ 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 ].…”

“…After doing this search, we realized that most studies performed with glioblastoma models varied only time of exposure [ 30 , 32 , 33 , 34 , 35 , 36 , 39 ] and almost no one studied the effects produced by different frequencies [ 30 ].…”

“…Furthermore, we observed that in many of the studies the field intensity used was remarkable greater than the recommended level for ELFs without explaining the reason that led to choosing each intensity [ 30 , 31 , 32 , 34 , 35 , 36 , 38 , 39 ].…”

Exposure to 50 Hz Extremely-Low-Frequency Magnetic Fields Induces No DNA Damage in Cells by Gamma H2AX Technology

“…Some similar studies showed insensitivity to ELF-MF in biological cells [ 12 ]. They found no evidence that ELF-MF could cause DNA damage in vivo or in vitro, as in human lens epithelial cells or neurogenic cells [ 13 – 16 ]. One hour of continuous and 75 min of intermittent (15 min power field on/15 min power field off) exposure indicated that MFs at power frequency may not cause DNA damage in cardiomyocytes [ 14 ].…”

Exposure to 50 Hz magnetic field at 100 µT exert no DNA damage in cardiomyocytes

“…However, McNamee et al did not detect any significant increase in DNA damage in rat or mouse brain cells after 2 h MF exposure (0–2 mT, 60 Hz) (McNamee et al, 2005). An in vitro study conducted by Su et al investigated both neurogenic tumor cell line cells and primary cultured neurogenic cells from rats exposed to 50 Hz MFs at 2 mT for up to 24 h, and no DNA damage effects were observed (Su et al, 2017). Using different methods of exposure, Focke et al found that intermittent (5 min on/10 min off) but not continuous exposure of human primary fibroblasts to a 50 Hz MF at 1 mT induced a slight but significant increase of DNA fragmentation (Focke et al, 2010).…”