Effects of electromagnetic fields on bone loss in hyperthyroidism rat model

Abstract

Optimal therapeutics for hyperthyroidism-induced osteoporosis are still lacking. As a noninvasive treatment, electromagnetic fields (EMF) have been proven to be effective for treating osteoporosis in non-hyperthyroidism conditions. We herein systematically evaluated the reduced effects of EMF on osteoporosis in a hyperthyroidism rat model. With the use of Helmholtz coils and an EMF stimulator, 15 Hz/1 mT EMF was generated. Forty-eight 5-month-old male Sprague-Dawley rats were randomly divided into four different groups: control, levothyroxine treated (L-T4), EMF exposure + levothyroxine (EMF + L-T4), and EMF exposure without levothyroxine administration (EMF). All rats were treated with L-T4 (100 mg/day) except those in control and EMF groups. After 12 weeks, the results obtained from bone mineral density analyses and bone mechanical measurements showed significant differences between L-T4 and EMF + L-T4 groups. Micro CT and bone histomorphometric analyses indicated that trabecular bone mass and architecture in distal femur and proximal tibia were augmented and restored partially in EMF + L-T4 group. In addition, bone thyroid hormone receptors (THR) expression of hyperthyroidism rats was attenuated in EMF + L-T4 group, compared to control group, which was not observed in L-T4 group. According to these results, we concluded that 15 Hz/1 mT EMF significantly inhibited bone loss and micro architecture deterioration in hyperthyroidism rats, which might occur due to reduced THR expression caused by EMF exposure. Bioelectromagnetics. 38:137-150, 2017. © 2016 Wiley Periodicals, Inc.

Extremely low frequency electromagnetic fields promote mesenchymal stem cell migration by increasing intracellular Ca2+ and activating the FAK/Rho GTPases signaling pathways in vitro

“…Finding a new treatment to promote MSC migration can bring new ideas to regenerative medicine and tissue engineering. EMF therapy has been proven to be an effective noninvasive approach in treating a wide range of bone diseases, such as fresh and nonunion fractures [ 36 , 37 ], osteoarthritis [ 38 ], and osteoporosis [ 39 – 41 ], both experimentally and clinically over the past decades. Our previous studies confirmed that EMF could significantly enhance the osteoblast differentiation of MSCs [ 23 , 42 – 44 ].…”

Electromagnetic field treatment increases purinergic receptor P2X7 expression and activates its downstream Akt/GSK3β/β-catenin axis in mesenchymal stem cells under osteogenic induction

“…EMF generated by the device were at frequency range of 0–100 Hz and an intensity range of 0–5.0 mT. A sinusoidal EMF was used as it showed a satisfactory effect in our previous studies [29, 30]. The intensity of the EMF was measured using a gauss meter (GM55A; TinDun Industry, Shanghai, China).…”

“…Scanco viva CT 40 instrument (Scanco, Brüttisellen, Switzerland) was used to scan the right femur and tibia excised from all groups of rats. The micro-structure of above bones was analyzed as reported in our previous study [30]. Briefly, contiguous cross-sectional images (10.5 μm) were obtained at 70 kV and 113 mA.…”

The cellular effects of Pulsed Electromagnetic Fields on osteoblasts: A review

“…The use of EMFs to promote bone healing is supported by abundant preclinical literature that shows their action in rodent models of glucocorticoid‐ or ovariectomy‐induced osteoporosis [Zati et al, ; Bilotta et al, ; Chang and Chang, ; Jing et al, , ; Zhou et al, , , , b; Jiang et al, ; Lei et al, ], disuse osteoporosis [Shen and Zhao, ; Jing et al, ; Li et al, ], osteoporotic fractures [Androjna et al, ], osteoarthritis [Yang et al, ], diabetes‐associated bone architecture [Li et al, ], hyperthyroidism bone loss [Liu et al, ], and bone healing [Takano‐Yamamoto et al, ; Sarker et al, ; Landry et al, ; Fredericks et al, ; Midura et al, ; Taylor et al, ; Bilgin et al, ; Huegel et al, ].…”