Intermittent Exposure to a 16 Hz Extremely Low Frequency Pulsed Electromagnetic Field Promotes Osteogenesis In Vitro through Activating Piezo 1-Induced Ca2+ Influx in Osteoprogenitor Cells

Yangmengfan Chen; Benedikt J Braun; Maximilian M Menger; Michael Ronniger; Karsten Falldorf; Tina Histing; Andreas K Nussler; Sabrina Ehnert

doi:10.3390/jfb14030165

Intermittent Exposure to a 16 Hz Extremely Low Frequency Pulsed Electromagnetic Field Promotes Osteogenesis In Vitro through Activating Piezo 1-Induced Ca²⁺ Influx in Osteoprogenitor Cells

J Funct Biomater. 2023 Mar 20;14(3):165. doi: 10.3390/jfb14030165.

Authors

Yangmengfan Chen¹, Benedikt J Braun¹, Maximilian M Menger¹, Michael Ronniger², Karsten Falldorf², Tina Histing¹, Andreas K Nussler¹, Sabrina Ehnert¹

Affiliations

¹ Siegfried Weller Institute at the BG Trauma Center Tübingen, Department of Trauma and Reconstructive Surgery, University of Tübingen, Schnarrenbergstr. 95, D-72076 Tübingen, Germany.
² Sachtleben GmbH, Haus Spectrum am UKE, Martinistraße 64, D-20251 Hamburg, Germany.

Abstract

Exposure to extremely low frequency pulsed electromagnetic fields (ELF-PEMF) is supposed to simulate local EMF generated during mechanical stimulation of bone and may therefore be used to improve bone regeneration. This study aimed at optimizing the exposure strategy and investigating the underlying mechanisms of a 16 Hz ELF-PEMF, previously reported to boost osteoblast function. Comparing influences of daily continuous (30 min every 24 h) and intermittent (10 min every 8 h) exposure to the 16 Hz ELF-PEMF on osteoprogenitor cells revealed that the intermittent exposure strategy enhanced the 16 Hz ELF-PEMF effects regarding cell numbers and osteogenic function. Gene expression of piezo 1 and related Ca²⁺ influx were significantly increased in SCP-1 cells with the daily intermittent exposure. Pharmacological inhibition of piezo 1 with Dooku 1 largely abolished the positive effect of the 16 Hz ELF-PEMF exposure on osteogenic maturation of SCP-1 cells. In summary, the intermittent exposure strategy enhanced the positive effects of 16 Hz continuous ELF-PEMF exposure in terms of cell viability and osteogenesis. This effect was shown to be mediated by an increased expression of piezo 1 and related Ca²⁺ influx. Thus, the intermittent exposure strategy is a promising way to further optimize the therapeutic effects of the 16 Hz ELF-PEMF regarding fracture healing or osteoporosis.

Keywords: bone; calcium ions; electromagnetic field; osteoprogenitor cells; piezo 1.

Grants and funding

ELF-PEMF devices were provided by Sachtleben GmbH. Y.C. received support from the Chinese Scholarship Council to cover his living expenses.