Effects of Pulsed Electromagnetic Field Therapy at Different Frequencies on Bone Mass and Microarchitecture in Osteoporotic Mice

Abstract

A pulsed electromagnetic field (PEMF) can promote osteogenesis. However, studies have shown variation in the signal characteristics in terms of waveform type, intensity, frequency, and treatment duration. Among the factors that affect electromagnetic fields, frequency plays a major role. However, few studies have investigated the effects of PEMF at different frequencies in osteoporotic mice. Therefore, our objective was to determine the effect of PEMF frequency in osteoporotic mice. Forty 3‐month‐old female mice were randomly divided into the following five groups: sham, OVX, and OVX followed by 1.6‐mT PEMF exposure groups (8 Hz, 50 Hz, and 75 Hz, 1.6 mT). The PEMF was applied for 1 h/day, 7 days/week, for 4 weeks. After 4 weeks, the micro‐computed tomography showed that PEMF with (50 and 75 Hz) ameliorated the deterioration of bone microarchitecture. Improvements in the bone histological analysis were identified for PEMF with 50 and 75 Hz groups compared with the ovariectomy (OVX) controls. Osteoclast numbers were decreased in PEMF with (50 and 75 Hz). Moreover, the real‐time PCR demonstrated PEMF with (50 and 75 Hz) significantly promoted the expression of the osteoblast‐related genes (ALP, OCN, Runx2), and increased the serum PINP. PEMF with (50 and 75 Hz) exerted significant inhibitory effects on the osteoclast‐related mRNA expression (CTSK, NFATc1, TRAP) and bone resorption markers CTX‐I and IL‐1β. Taken together, our results showed that PEMF at 50 and 75 Hz with 1.6 mT significantly ameliorate the deterioration of bone microarchitecture in OVX mice. The inhibitory effect of PEMF may be associated with IL‐1β inhibition. © 2021 Bioelectromagnetics Society.

The Effect of Different Frequencies of Pulsed Electromagnetic Fields on Cartilage Repair of Adipose Mesenchymal Stem Cell–Derived Exosomes in Osteoarthritis

“…Our previous study stated that PEMF at 75 Hz is superior to low-frequency PEMF in ameliorating the deterioration of bone microarchitecture in ovariectomized (OVX) mice, and the inhibitory effect of PEMF may be associated with IL-1β inhibition. 31 , 50 Thus, we designed the experiment that stimulated MSCs with PEMF at an amplitude of 1 mT and a frequency of 15, 45, and 75 Hz respectively. In the present study, the 75-Hz PEMF-exposed AMSC-derived exosomes significantly inhibited IL-1β, MMP13, and caspase-1 levels in the IL-1β-induced chondrocytes.…”

Biophysical Modulation of the Mitochondrial Metabolism and Redox in Bone Homeostasis and Osteoporosis: How Biophysics Converts into Bioenergetics

“…Pulsed electromagnetic fields intervention for 4 weeks compromises the loss in trabecular microstructure and morphology together with increased osteogenic gene expression and reduced osteoclastogenic gene expression in bone tissue of ovariectomized mice [56]. The protection effects of 30 T/s pulsed electromagnetic field intervention on cortical bone microstructure and resorption in ovariectomized rats are comparable to the anti-resorptive effect of alendronate medication [57].…”

Pulsed Electromagnetic Field Promotes Bone Anabolism in Postmenopausal Osteoporosis through the miR-6976/BMP/Smad4 Axis

“…Te PEMF stimulation parameter was based on our previous data: square wave/1.6 mT/75 Hz. [28][29][30]. We used a handheld Gaussian meter (HT201; Hengtong, China) to measure the magnetic feld intensity.…”