Combined Effects of Low‐Frequency Pulsed Electromagnetic Field and Melatonin on Ovariectomy‐Induced Bone Loss in Mice

Abstract

Pulsed electromagnetic field (PEMF) therapy and melatonin (MEL) supplementation are expected to be important strategies for the treatment of osteoporosis. The aim of the current study was to investigate the efficacy of PEMF therapy, MEL supplementation, a combination of PEMF therapy, and MEL supplementation (PEMF + MEL) in mice with bilateral ovariectomy (OVX)-induced osteoporosis. Forty 12-week-old female C57/BL mice were randomly assigned to five groups (n = 8/group): OVX, PEMF, MEL, PEMF + MEL, and sham-operation (sham) groups. All mice in the first four groups were subjected to OVX. The mice in the PEMF and PEMF + MEL groups were exposed to PEMF (75 Hz, 1.6 mT, 1 h/day for 12 weeks), while those in the MEL and PEMF + MEL groups were administered MEL (50 mg/kg, i.p.). Body mass, micro-computed tomography, histology, immunohistochemistry, and real-time polymerase chain reaction were performed. PEMF + MEL treatment enhanced bone volume fraction (BV/TV) 2.2-fold over OVX control (P < 0.001) and increased expression levels of collagen type I (COL1) 1.9-fold and bone morphogenetic protein 2 (BMP2) 2.5-fold. PEMF + MEL also reduced the ratio of bone surface/ bone volume (BS/BV) by 40% (P < 0.05) and appeared to reduce the number of osteoclasts in the metaphysis area. Preservation of bone value and bone microarchitecture in the combined therapy group were found to be superior to those in the single treatment groups. However, there were no apparent differences between the PEMF and MEL groups. The use of a combination of PEMF therapy and MEL supplementation may be an effective method to treat osteoporosis.

The role of melatonin in the development of postmenopausal osteoporosis

“…Melatonin feeding could improve bone mass and relieve bone loss in OVX mice (Gürler et al, 2019). Histological detection of bone tissues indicated that melatonin increases the expression of Collagen I and BMP2 but decreases the expression of PRMT1 and TRAP (Choi et al, 2021;Huang et al, 2021). These data demonstrate that melatonin has positive effects on osteogenesis and negative effects on osteoclastogenesis in animal models, which is consistent with the results at the cellular level.…”

Influence of Various Strontium Formulations (Ranelate, Citrate, and Chloride) on Bone Mineral Density, Morphology, and Microarchitecture: A Comparative Study in an Ovariectomized Female Mouse Model of Osteoporosis

“…In total, 10 females from the sham group underwent a sham ovariectomy (sham). During sham surgery, the animals underwent a similar procedure, except for the removal of the ovaries [55,56].…”

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.…”

“…We used a handheld Gaussian meter (HT201; Hengtong, China) to measure the magnetic feld intensity. Details of the PEMF exposure device can be found in our previous studies [28].…”

“…We used real-time PCR to determine the mRNA levels of osteogenesis-related genes (Runx2, Osx, etc.) [28]. Te primer sequences are shown in Table S1 Detection of bone mineralization and osteogenic activity: cells were fxed with 4% paraformaldehyde at 25 °C for 30 min, washed three times with PBS, stained with Alizarin Red Stain (ARS) solution (Cyagen, China) at room temperature, protected from light for 10 min, washed three more times, and photographed under a microscope.…”