A 700 MHz 1H-NMR study reveals early signs of apoptosis-like behavior in human K562 erythroleukemic cells exposed to a 50 Hz sinusoidal magnetic field

Purpose: To study cell damage and possible apoptosis in K562 human erythroleukemic cells exposed for 2?h to an extremely low frequency (ELF) 50 Hz sinusoidal magnetic field with a magnetic induction of either 1 or 5 mT using high resolution proton nuclear magnetic resonance (1H-NMR) spectroscopy. Materials and methods: One-dimensional 1H-NMR spectra were obtained on whole K562 cells and perchloric acid extracts of these cells. In addition, two-dimensional 1H-NMR spectra were also acquired. Cell damage was examined by lactate dehydrogenase release and changes in cell growth were monitored by growth curve analyses, bromodeoxyuridine incorporation, and Ki67 antigen localization. Cell death (necrosis and apoptosis) was also studied by using the chromatin dye Hoechst 33258. Results: The variations in numerous metabolites observed with 1H-NMR reveal apoptosis-like behavior in response of K562 cells to ELF fields. Conclusion:1H-NMR can be extremely useful in studying the effects of ELF fields on cells. In particular, the variations in metabolites, which suggest apoptosis-like behavior, occur when the cells are not identifiable as apoptotic by more traditional techniques.