Extremely low-frequency electromagnetic fields facilitate both osteoblast and osteoclast activity through Wnt/β-catenin signaling in the zebrafish scale

Jingjing Kobayashi-Sun; Isao Kobayashi; Makoto Kashima; Jun Hirayama; Makiko Kakikawa; Sotoshi Yamada; Nobuo Suzuki

doi:10.3389/fcell.2024.1340089

Extremely low-frequency electromagnetic fields facilitate both osteoblast and osteoclast activity through Wnt/β-catenin signaling in the zebrafish scale

Front Cell Dev Biol. 2024 Feb 7:12:1340089. doi: 10.3389/fcell.2024.1340089. eCollection 2024.

Authors

Jingjing Kobayashi-Sun^{1

2}, Isao Kobayashi², Makoto Kashima³, Jun Hirayama¹, Makiko Kakikawa², Sotoshi Yamada^{4

5}, Nobuo Suzuki⁵

Affiliations

¹ Department of Clinical Engineering, Faculty of Health Science, Komatsu University, Komatsu, Ishikawa, Japan.
² Faculty of Biological Science and Technology, Institute of Science and Engineering, Kanazawa University, Kanazawa, Ishikawa, Japan.
³ Department of Biomolecular Science, Faculty of Science, Toho University, Funabashi, Chiba, Japan.
⁴ Department of Production System Engineering and Sciences, Faculty of Production System Engineering and Sciences, Komatsu University, Komatsu, Ishikawa, Japan.
⁵ Noto Marine Laboratory, Institute of Nature and Environmental Technology, Kanazawa University, Kanazawa, Ishikawa, Japan.

Abstract

Electromagnetic fields (EMFs) have received widespread attention as effective, noninvasive, and safe therapies across a range of clinical applications for bone disorders. However, due to the various frequencies of devices, their effects on tissues/cells are vary, which has been a bottleneck in understanding the effects of EMFs on bone tissue. Here, we developed an in vivo model system using zebrafish scales to investigate the effects of extremely low-frequency EMFs (ELF-EMFs) on fracture healing. Exposure to 10 millitesla (mT) of ELF-EMFs at 60 Hz increased the number of both osteoblasts and osteoclasts in the fractured scale, whereas 3 or 30 mT did not. Gene expression analysis revealed that exposure to 10 mT ELF-EMFs upregulated wnt10b and Wnt target genes in the fractured scale. Moreover, β-catenin expression was enhanced by ELF-EMFs predominantly at the fracture site of the zebrafish scale. Inhibition of Wnt/β-catenin signaling by IWR-1-endo treatment reduced both osteoblasts and osteoclasts in the fractured scale exposed to ELF-EMFs. These results suggest that ELF-EMFs promote both osteoblast and osteoclast activity through activation of Wnt/β-catenin signaling in fracture healing. Our data provide in vivo evidence that ELF-EMFs generated with a widely used commercial AC power supply have a facilitative effect on fracture healing.

Keywords: Wnt/β-catenin signaling; electromagnetic fields; osteoblast; osteoclast; zebrafish scale.

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. This work was supported in part by a Grant-in-Aid for JSPS Fellows (22KJ2574), a Grant-in-Aid for Early-Career Scientists (23K14111), a Grant-in-Aid for Scientific Research C (23K10933) from the Japan Society for the Promotion of Science, and Watanabe Foundation (01108).