Pulsed electromagnetic fields inhibit bone loss in streptozotocin-induced diabetic rats

Abstract

Evidences have shown that pulsed electromagnetic fields (PEMFs) can partially prevent bone loss in streptozotocin (STZ)-induced diabetic rats. However, the precise mechanisms accounting for these favorable effects are unclear. This study aimed to investigate the effects of PEMFs on bone mass and receptor activator of nuclear factor κB ligand (RANKL)/osteoprotegerin (OPG) and Wnt/β-catenin signaling pathway in STZ rats. Thirty 3-month-old Sprague Dawley rats were randomly divided into the following three groups (n = 10): control group (injection of saline vehicle), DM group (injection of STZ), and PEMFs group (injection of STZ + PEMFs exposure). One week following injection of STZ, rats in the PEMFs group were subject to PEMFs stimulus for 40 min/day, 5 days/week, and lasted for 12 weeks. After 12 week intervention, the results showed that PEMFs increased serum bone-specific alkaline phosphatase level and bone mineral density, and inhibited deterioration of bone microarchitecture and strength in STZ rats. Furthermore, PEMFs up-regulated the mRNA expressions of low-density lipoprotein receptor-related protein 5, β-catenin and runt-related gene 2 (Runx2), and down-regulated dickkopf1 in STZ rats. However, mRNA expressions of RANKL and OPG were not affected by PEMFs. PEMFs can prevent the diabetes-induced bone loss and reverse the deterioration of bone microarchitecture and strength by restoring Runx2 expression through regulation of Wnt/β-catenin signaling, regardless of its no glucose lowering effect.

Sinusoidal Electromagnetic Fields Increase Peak Bone Mass in Rats by Activating Wnt10b/β-Catenin in Primary Cilia of Osteoblasts

“…The roles of the different Wnt ligands in bone homeostasis and bone diseases are not yet fully understood. There have been many clinical trials and experimental studies reporting that PEMFs modulate bone metabolism through the Wnt/β‐catenin pathway . However, few researchers have investigated the Wnt ligands involved in the process, except for Wnt1 and Wnt3a .…”

Effects of electromagnetic fields on osteoporosis: A systematic literature review

“…Zhou et al treated the ovariectomy rats with PEMFs (8 Hz, 3.82 mT, 40 min/ d) for 12 weeks and found that PEMFs could prevent ovariectomy-induced bone loss and deterioration of bone microarchitecture and strength, at least partly, through the activation of Wnt/β-catenin signaling pathway (Zhou et al, 2012). Then, they treated bone loss in streptozotocin-induced diabetic rats with the same parameter of PEMFs and documented that PEMFs could prevent the diabetes-induced bone loss and reverse the deterioration of bone microarchitecture (Zhou et al, 2014) …”

Effects of pulsed electromagnetic fields on postmenopausal osteoporosis

“…Moreover, results from our research group [Zhou et al, , ] demonstrated that PEMFs with the parameters of 8 Hz and 3.8 mT (40 min/day, 5 days/week for 12 weeks) could mitigate the deterioration of bone microarchitecture and strength, as was evidenced by histological and biomechanical analyses. Meanwhile, other research groups also reported that PEMFs with the same parameters (8 Hz, 3.8 mT, 40 min/day, 5 days/week for 12 weeks) had the same beneficial effect via significantly increasing BMD (DEXA), bone mechanical properties, and parameters of µCT (including trabecular bone volume ratio, trabecular number, trabecular thickness, and separation) in streptozotocin‐ and ovariectomy‐induced bone loss, respectively [Zhou et al, , ]. However, it was suggested in a study [van der Jagt et al, ] that the efficacy of PEMFs with the parameters of 15 Hz and 1 G (2 h/day for 3–6 weeks) might be a source of controversy since micro‐CT scanning could not detect any changes in cancellous or cortical bone relative to the untreated controls.…”

“…PEMFs displayed a marked preventive effect on osteoporosis‐induced high bone turnover in rat models. Results of several studies (Table ) supported that PEMFs could significantly increase levels of biomarkers of osteoblast‐associated bone formation, such as serum bone‐specific alkaline phosphatase (BALP), OC, and P1NP, but they produced only minor preventive effects on biomarkers of osteoclast‐associated bone resorption [Jing et al, , ; Zhou et al, ], such as serum C‐terminal crosslinked telopeptides of type I collagen (CTX‐I) and tartrate‐resistant acid phosphatase 5b (TRAcP5b). Effects of PEMF on bone loss might be related to significantly improved bone formation when taking the positive change of bone mass into consideration.…”