50 Hz Electromagnetic Field Produced Changes in FTIR Spectroscopy Associated with Mitochondrial Transmembrane Potential Reduction in Neuronal-Like SH-SY5Y Cells

Abstract

SH-SY5Y neuroblastoma cells were used as an experimental model to study the effects of 50 Hz electromagnetic field, in the range from 50 µT to 1.4 mT. Fourier transform infrared spectroscopy analysis evidenced a reduction in intensity of the amide A band and a slight increase of vibration bands at 2921 cm−1 and 2853 cm−1 corresponding to methylene groups. A further increase of the magnetic field intensity of exposure up to 0.8 mT and 1.4 mT produced a clear increase in intensity of CH2 vibration bands. Moreover, it has been observed some alterations in the amide I region, such as a shifted peak of the amide I band to a smaller wavenumber, probably due to protein conformational changes. These results suggested that exposure to extremely low electromagnetic fields influenced lipid components of cellular membrane and the N–H in-plane bending and C–N stretching vibrations of peptide linkages, modifying the secondary structures of α-helix and β-sheet contents and producing unfolding process in cell membrane proteins. The observed changes after exposure to 50 Hz electromagnetic field higher than 0.8 mT were associated with a significant reduction of cell viability and reduced mitochondrial transmembrane potential.

Comparative Analysis of Biological Effects Induced on Different Cell Types by Magnetic Fields with Magnetic Flux Densities in the Range of 1–60 mT and Frequencies up to 50 Hz

“…For example, a 50 Hz, 1-50 mT, ELF-PMF induces non-linear changes in both cell membrane conductivity and permittivity in in vitro-cultivated primary embryonic chicken myoblasts after 1 h of exposure; conversely, when the same cells are exposed for 1 h to a DC-induced SMF of 1, 3, or 5 mT, i.e., values comparable with those of the ELF-PMF used in the same study, no change in the same membrane electrical parameters was observed in comparison to control values [3,4]. MF exposure also induces variations in the inner mitochondrial transmembrane potential of differentiated U937 (6 mT, for up to 72 h) and SH-SY5Y cells (1.4 mT, 50 Hz, ELF-PMF, for up to 4 h) [16,17]. Interestingly, these experimental observations have been mathematically rationalized by Ye et al, (2010).…”

“…As an endpoint, a significant reduction of the DNA content is observed following exposure [17]. No significant differences were found about cell viability between sham exposed and 2 mT, 50 Hz, ELF-PMF exposed Raji cells up to 72 h [19], whereas HaCaT cells exposed to the same MF, but for a longer time (up to 15 days), showed an increase in both clonogenic capacity and cell growth than controls [31].…”

“…This molecular rotation within the membrane matrix influences the imbedded ion channels, most likely by producing some degree of deformity of their intramembranous segment, i.e., the part of the structure which is responsible for activation [22,23]. ELF-PMF exposure also influences the lipid components of the cellular membrane, and the N-H in-plane bending and C-N stretching vibrations of peptide linkages, modifying the secondary structures of α-helix and β-sheet contents and producing unfolding process in cell membrane proteins of Hela (41.7-43.6 mT, 50 Hz, ELF-PMF, for up to 1 min) and differentiated SH-SY5Y cells (0.81-1.41, 50 Hz, ELF-PMF, for up to 4 h) [17,24]. Thus, MF affects membrane proteins either directly, or indirectly through the neighbouring phospholipids [17,22,23].…”

Non-Resonant Frequencies of Electromagnetic Fields in α-Helices Cellular Membrane Channels

“…In this scenario, the resonant frequencies in cellular membrane channels can be found measuring the displacement of the α-helices in membranes channels as a function of the frequency of an applied EMF, following the protocol accurately described in [13,15]. For instance, Circular Dichroism (CD) spectroscopy can be used to measure the shift of the alpha helix with respect to its resting position in the cellular membrane channels as a function of the frequency of an applied EMF.…”

FTIR Spectroscopy Analysis can Highlight Induced Damage in Neuronallike Cells and Bio-protective Effectiveness of Agmatine

“…Mid-infrared (IR) spectra were collected in the range 4000-1200 cm -1 by means of 64 interferograms using a spectral resolution of 4 cm -1 . In addition, baseline-correction and area-normalization were used to treat and control samples, following the procedure described in Calabrò and Magazù [21,22]. Finally, Fourier Self-Deconvolution (FSD) analysis was used to provide more qualitative information.…”