To observe the effect of pulsed electromagnetic fields (PEMFs) of different treatment time on bone mineral density of femur in ovariectomized rats, so as to find out the treatment time for the best therapeutic efficacy. Methods Fifty female SD rats were randomly divided into 5 groups: sham-ovariectomized (SHAM) group (no PEMFs treatment), ovariectomy (OVX) control group (no PEMFs treatment), OVX I, II and III groups (PEMFs treatment at 8 Hz frequency with 3. 8 ×10-10A/m intensity 20, 40, and 60 minutes daily for 30 days, respectively). All rats were given bilateral ovariectomy except those in the SHAM control group. Bone mineral density (BMD) of femur was assessed at 30 days after PEMFs treatment. Results In OVX control group, hypotrichosis, hypoactivity and l istlessness were observed after operation; and in SHAM group, OVX I group, OVX II group and OVX III group, pilus, psyche and activity were normal. The BMD values were (0.226 ± 0.011), (0.210 ± 0.011), (0.231 ± 0.013), (0.231 ± 0.017) and (0.229 ± 0.013) g/cm2 in SHAM group, OVX control group, OVX I group, OVX II group and OVX III group respectively, showing significant differences between OVX control group and other groups (P lt; 0.05), but showing no significant differences between other 4 groups (P gt; 0.05). Conclusion P EMFs of the three different treatment times can maintain the BMD in ovariectomized rats. It shows that PEMFs have the same effect of maintaining BMD with increasing of treatment time at the range of 20-60 minutes in ovariectomized rats.
ObjectiveTo compare the clinical effects of pulsed electromagnetic fields (PEMFs) with oral alendronate in the treatment of postmenopausal osteoporosis. MethodsFourty patients diagnosed to have postmenopausal osteoporosis (OP) from September 2009 to September 2010 were included in our study. They were randomly divided into the experimental group and the control group. All patients were administered the same basic drugs:Caltrate 600 mg and Alfacalcidol 0.5 μg per day. For the experimental group, PEMFs were offered 6 times per week for 5 weeks (30 times in total), and patients in this group were followed up for 12 weeks. For the control group, alendronate was given at a dose of 70 mg per week for 12 weeks. Bone mineral density (BMD), visual analogue scale, and manual muscle testing (MMT) scale were evaluated before, 1 week, 5 weeks, and 12 weeks after intervention. ResultsIncreasing of BMD, pain relieving, and improvement of MMT had a trend of increasing values after 5 weeks of treatment in the experimental group (P<0.05), but there was no significant difference between the two groups (P>0.05). However, there was a significant difference between the two groups in patients' lower back muscle strength after treatment (P<0.05). ConclusionPEMFs have the same effect as alendronate in pain relief, and bone mass and muscle strength improvement, and are even advantageous in increasing back muscle strength compared with alendronate.
ObjectiveTo investigate whether signal molecule mitogen-activated protein kinases (MAPKs) involves in the process of the mineralization and maturation of rat calvarial osteoblasts promoted by 50 Hz, 0.6 mT pulsed electromagnetic fields. MethodsRat calvarial osteoblasts were obtained by enzyme digestion from the skull of 6 neonatal Wistar rats of SPF level. The primary osteoblasts were treated in 50 Hz and 0.6 mT pulsed electromagnetic fields for 0, 5, 10, 20, 40, 60, and 120 minutes; the protein expression of phosphorylated MAPKs was detected by Western blot. The osteoblasts were randomly divided into group A (control group), group B (low frequency pulse electromagnetic fields treatment group), group C (SB202190 group), and group D (SB202190+low frequency pulse electromagnetic fields treatment group); the alkaline phosphatase (ALP) activities were tested after corresponding treatment for 1, 4, and 7 days. The corresponding treated more than 90% confluenced osteoblasts were cultured under condition of osteogenic induction, then ALP staining and alizarin red staining were carried out at 9 and 12 days respectively. ResultsThe results of Western blot showed that there was no significant changes in the protein expressions of phosphorylated level of extracellular signal-related kinases 1/2 and c-Jun amino N-terminal kinases 1/2 in 50 Hz, 0.6 mT pulsed electromagnetic fields P>0.05), but the phosphorylated level of p38 began to increase at 5 minutes, peaked at 40 minutes, then gradually decreased, and it was significantly higher at 5-120 minutes than at 0 minute (P<0.05). After the activities of p-p38 was inhibited by inhibitor SB202190, the ALP activities, positive colonies and area of ALP and calcified nodules of group B were significantly higher than groups A, C, and D (P<0.05). Conclusionp38 is one of the signal molecules involved in the process of the mineralization and maturation of rat calvarial osteoblasts promoted by 50 Hz, 0.6 mT pulsed electromagnetic fields.
With the acceleration of the aging in the world and our society, osteoarthritis has become a health concern for patients and health workers. At present, its treatment mainly relies on drug treatment, surgical treatment and rehabilitation. As a safe, non-invasive and simple treatment, pulsed electromagnetic field (PEMF) therapy has been used in clinical treatment of osteoporosis, promoting fracture healing and improving symptoms of osteoarthritis. However, the mechanism of PEMF in the treatment of knee osteoarthritis is still unclear. This paper reviews the effects of PEMF on apoptosis, cytokines, cartilage and subchondral bone in knee osteoarthritis in animal experiments, and the changes of chondrocyte morphology and extracellular matrix in cell experiments, aiming to enable medical workers to better understand the status and development of PEMF in the treatment of knee osteoarthritis in basic experimental researches.
The study aims to explore the effect of mesenchymal stem cells-derived exosomes (MSCs-Exo) on staurosporine (STS)-induced chondrocyte apoptosis before and after exposure to pulsed electromagnetic field (PEMF) at different frequencies. The AMSCs were extracted from the epididymal fat of healthy rats before and after exposure to the PEMF at 1 mT amplitude and a frequency of 15, 45, and 75 Hz, respectively, in an incubator. MSCs-Exo was extracted and identified. Exosomes were labeled with DiO fluorescent dye, and then co-cultured with STS-induced chondrocytes for 24 h. Cellular uptake of MSC-Exo, apoptosis, and the protein and mRNA expression of aggrecan, caspase-3 and collagenⅡA in chondrocytes were observed. The study demonstrated that the exposure of 75 Hz PEMF was superior to 15 and 45 Hz PEMF in enhancing the effect of exosomes in alleviating chondrocyte apoptosis and promoting cell matrix synthesis. This study lays a foundation for the regulatory mechanism of PEMF stimulation on MSCs-Exo in inhibiting chondrocyte apoptosis, and opens up a new direction for the prevention and treatment of osteoarthritis.