Proteomics of human primary osteoarthritic chondrocytes exposed to extremely low-frequency electromagnetic fields (ELF EMFs) and to therapeutic application of musically modulated electromagnetic fields (TAMMEF)

Abstract

Osteoarthritis (OA) is the most frequent joint disease, characterized by degradation of extracellular matrix and alterations in chondrocyte metabolism. Some authors reported that electromagnetic fields (EMFs) can positively interfere with patients affected by OA, even though the nature of the interaction is still debated. Human primary osteoarthritic chondrocytes isolated from the femoral heads of OA-patients undergoing to total hip replacement, were cultured in vitro and exposed 30 min/day for two weeks to extremely-low-frequency electromagnetic field (ELF) with fixed frequency (100 Hz) and to therapeutic application of musically modulated electromagnetic fields (TAMMEF) with variable frequencies, intensities and waveforms. Sham-exposed (S.E.) cells served as control group. Cell viability was measured at days 2, 7 and 14. After two weeks, cell lysates were processed using a proteomic approach. Chondrocyte exposed to ELF and TAMMEF system demonstrated different viability compared to untreated chondrocytes (S.E.). Proteome analysis of 2D-Electrophoresis and protein identification by mass spectrometry showed different expression of proteins derived from nucleus, cytoplasm and organelles. Function analysis of the identified proteins showed changes in related-proteins metabolism (glyceraldeyde-3-phosphate-dehydrogenase), stress response (Mn-superoxide-dismutase, heat-shock proteins), cytoskeletal regulation (actin), proteinase inhibition (cystatin-B) and inflammation regulatory functions (S100-A10, S100-A11) among the experimental groups (ELF, TAMMEF and S.E.). In conclusion, EMFs do not cause damage to chondrocytes, besides stimulate safely OA-chondrocytes and are responsible of different protein expression among the three groups. Furthermore, protein analysis of OA-chondrocytes treated with ELF and the new TAMMEF systems could be useful to clarify the pathogenetic mechanisms of OA by identifying biomarkers of the disease.

Cellular Response to ELF-MF and Heat: Evidence for a Common Involvement of Heat Shock Proteins?

“…In contrast to the absence of effects in the studies above, exposure has also caused changes in HSP levels in a number of primary or non-transformed (“primary like”) cell lines. The effects were seen as an induction of HSP genes on both the mRNA and protein levels in various cell types such as human primary osteoarthritic chondrocytes ( 36 ), mouse macrophages ( 37 ), transfected rat primary fibroblasts (RAT1 cells) ( 38 ), transfected rat primary cells ( 39 ) or cardiomyocytes isolated from neonatal Sprague-Dawley rats ( 40 ), porcine aortic endothelial cells ( 41 ), endothelial cells (SPAE, HUVECs), and human fibroblasts (HuDe, WI-38) ( 42 ). Considering that the basal level of HSPs expression is strongly cell type dependent, it can be hypothesized that primary cells or primary-like cell lines have a lower basal HSPs level, and thus that these cells are rather easier inducing HSPs than cancer cell lines.…”

Effect of electromagnetic fields on human osteoarthritic and non-osteoarthritic chondrocytes

“…In addition, EMFs may have anti-apoptotic effects by decreasing the expression of proteins involved in the pro-apoptotic pathway and simultaneously increasing expression of anti-apoptotic proteins [ 30 ]. EMF treatment seems to improve suboptimal or degenerate cellular conditions for chondrocytes [ 31 , 32 ]. In the absence of chondrocyte stress EMFs may be ineffective which may in part explain the lack of EMF effect in some studies.…”

Extremely Low-Frequency Magnetic Field as a Stress Factor—Really Detrimental?—Insight into Literature from the Last Decade

“…Targets for ELF-MF at molecular level include the cell membrane (e.g., its permeability, inorganic ion transport, receptor function), second messengers synthesis, chromosome structural changes and chemical changes in DNA structure, genes expression and protein synthesis (e.g., metabolism-related), free radicals, and neurotrophic factors. Such profound modifications have to be reflected in neurotransmitter activity, hormone release, and metabolism of the brain [36][37][38][39][40][41][42][43][44]. What is important, the effect of ELF-MF on molecular and/or cellular mechanisms is not obvious-it can be detrimental or protective.…”

“…As shown in in vivo research, ELF-MF can affect levels and function of proteins-crucial for maintenance of cell homeostasis, e.g., proteins anchored in lipid bilayer of the cell membrane functioning as ion channels, enzymes, and receptors, as well as the other proteins of key importance for the response to stress, regulation of apoptosis, and a number of metabolic processes [37,45,47,49,50]. Total protein level as well as its activity (e.g., alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (ALP), albumin, bilirubin) was augmented in rats exposed to 1.5 mT ELF-MF [45].…”