Cell physiological responses of RAW264 macrophage cells to a 50-Hz magnetic field

Chihiro Nishigaki, Maresuke Nakayama, Hidetake Miyata

Research output: Contribution to journalArticlepeer-review

Abstract

Purpose: We previously showed that a 0.5-mT, 50-Hz sinusoidal magnetic field (LFMF) enhanced DNA single-strand breaks (SSB) and necrosis in RAW264 macrophages that had been stimulated by bacterial endotoxin (lipopolysaccharide; LPS). LPS enhances production of nitric oxide (NO) and superoxide anion (O2) that react with each other to generate peroxynitrite (ONOO). ONOO causes DNA strand breaks. Hence, we anticipated that 0.5-mT, 50-Hz sinusoidal magnetic field increased production of NO, thereby increasing intracellular ONOO concentration and promoted DNA strand breaks. However, the NO production was not increased. In this study, we examined if the exposure of the cell to 0.5-mT, 50-Hz magnetic field for 24 h (1) promotes O2 production, (2) elevated the degree of apoptosis, because apoptosis is an upstream event of necrosis, (3) lowers mitochondrial membrane potential (ΔΦm), because it would also promote necrosis. Materials and methods: O2, was measured with nitroblue tetrazolium and water-soluble tetrazolium salt. Necrosis and apoptosis were quantified with propidium iodide and fluorescence labelling of caspases, respectively. The ΔΦm was measured with a fluorescent probe (JC-1) that reflects ΔΦm. Results and conclusions: In the LPS-stimulated macrophage, the LFMF did not promote O2 production. Thus, the LFMF-promoted DNA strand breaks did not result from the increase in the O2 production. The LFMF did not promote apoptosis, whereas it tended to increase the degree of necrosis, as we showed previously. The ΔΦm slightly declined in the LFMF-exposed cell without statistical significance.

Original languageEnglish
Pages (from-to)1628-1632
Number of pages5
JournalInternational Journal of Radiation Biology
Volume96
Issue number12
DOIs
Publication statusPublished - 2020

Keywords

  • Low frequency magnetic field
  • mitochondria
  • peroxynitrite

ASJC Scopus subject areas

  • Radiological and Ultrasound Technology
  • Radiology Nuclear Medicine and imaging

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