Effects Of Pulsed Electromagnetic Fields Research Articles

Pulsed electromagnetic field may accelerate in vitro endochondral ossification.

Recapitulation of embryonic endochondral bone formation is a promising alternative approach to bone tissue engineering. However, the time-consuming process is one of the reasons the approach is unpractical. Here, we aimed at accelerating the in vitro endochondral ossification process of tissue engineering by using a pulsed electromagnetic field (PEMF). The rat bone marrow-derived stem cells were chondrogenic or hypertrophic differentiated in a three-dimensional pellet culture system, and treated with different intensities of PEMF (1, 2, and 5 mT with modulation frequency 750 Hz, carrier frequency 75 Hz and a duty ratio of 0.8, 3 h/day for 4 weeks). The effects of PEMF on hypertrophy and endochondral ossification were assessed by safranin O staining, immunohistochemistry, and quantitative real-time polymerase chain reaction. The results suggest that PEMF at 1, 2, and 5 mT may inhibit the maintenance of the cartilaginous phenotype and increase cartilage-specific extracellular matrix degradation in the late stage of chondrogenic differentiation. In addition, among the three different intensities, only PEMF at 1 mT directed the differentiation of chondrogenic-induced stem cell pellets to the hypertrophic stage and promoted osteogenic differentiation. Our findings provide the feasibility to optimize the process of in vitro endochondral ossification with PEMF stimulation.

Increases in microvascular perfusion and tissue oxygenation via pulsed electromagnetic fields in the healthy rat brain.

High-frequency pulsed electromagnetic field stimulation is an emerging noninvasive therapy being used clinically to facilitate bone and cutaneous wound healing. Although the mechanisms of action of pulsed electromagnetic fields (PEMF) are unknown, some studies suggest that its effects are mediated by increased nitric oxide (NO), a well-known vasodilator. The authors hypothesized that in the brain, PEMF increase NO, which induces vasodilation, enhances microvascular perfusion and tissue oxygenation, and may be a useful adjunct therapy in stroke and traumatic brain injury. To test this hypothesis, they studied the effect of PEMF on a healthy rat brain with and without NO synthase (NOS) inhibition. In vivo two-photon laser scanning microscopy (2PLSM) was used on the parietal cortex of rat brains to measure microvascular tone and red blood cell (RBC) flow velocity in microvessels with diameters ranging from 3 to 50 μm, which includes capillaries, arterioles, and venules. Tissue oxygenation (reduced nicotinamide adenine dinucleotide [NADH] fluorescence) was also measured before and for 3 hours after PEMF treatment using the FDA-cleared SofPulse device (Ivivi Health Sciences, LLC). To test NO involvement, the NOS inhibitor N(G)-nitro-l-arginine methyl ester (L-NAME) was intravenously injected (10 mg/kg). In a time control group, PEMF were not used. Doppler flux (0.8-mm probe diameter), brain and rectal temperatures, arterial blood pressure, blood gases, hematocrit, and electrolytes were monitored. Pulsed electromagnetic field stimulation significantly dilated cerebral arterioles from a baseline average diameter of 26.4 ± 0.84 μm to 29.1 ± 0.91 μm (11 rats, p < 0.01). Increased blood volume flow through dilated arterioles enhanced capillary flow with an average increase in RBC flow velocity by 5.5% ± 1.3% (p < 0.01). Enhanced microvascular flow increased tissue oxygenation as reflected by a decrease in NADH autofluorescence to 94.7% ± 1.6% of baseline (p < 0.05). Nitric oxide synthase inhibition by L-NAME prevented PEMF-induced changes in arteriolar diameter, microvascular perfusion, and tissue oxygenation (7 rats). No changes in measured parameters were observed throughout the study in the untreated time controls (5 rats). This is the first demonstration of the acute effects of PEMF on cerebral cortical microvascular perfusion and metabolism. Thirty minutes of PEMF treatment induced cerebral arteriolar dilation leading to an increase in microvascular blood flow and tissue oxygenation that persisted for at least 3 hours. The effects of PEMF were mediated by NO, as we have shown in NOS inhibition experiments. These results suggest that PEMF may be an effective treatment for patients after traumatic or ischemic brain injury. Studies on the effect of PEMF on the injured brain are in progress.

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

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.

Evaluation of the effect of pulsed electromagnetic fields on osseointegration of immediate dental implants

Evaluation of the effect of pulsed electromagnetic fields on osseointegration of immediate dental implants

Efficacy of Pulsed Electromagnetic Field in Treatment of Primary Dysmenorrhea.

To investigate the effect of pulsed electromagnetic field (PEMF) in treatment of  primary dysmenorrhea.

Влияние импульсных электромагнитных полей частотой 5 ГЦ. на биохимические показатели крови у крыс линии вистар

Biological effect of electromagnetic fields on an organism of persons and animals were investigated quite a lot. The observed effects, if they occur, are still unclear and difficult to determine, therefore, this issue remains relevant. Recently many sources of electromagnetic radiations work in a pulse mode. From all variety of electromagnetic fields most biologically active are considered the pulsed electromagnetic fields (PEMF). According to some information the impulse of radical categories can exceed 3 kW/m, but in their study it is necessary to consider a variety of parameters defining the bioeffects and to predict the consequences of influences of ubiquitous EMF. The experimental results received by authors for the last year, devoted to study of biochemical indicators of blood in the rats at the effects of pulsed electromagnetic fields were systematized and analyzed in this paper. PEMF effect was carried out with a frequency of 5 Hz. 5 in the sessions of PEMF for 30 minutes per each within four weeks. The obtained data are mathematically processed. The results of comparison of these data with control group of indicators allowed to revealing the pathological changes at PEMF impact with a frequency of 5 Hz on blood in the rats.

Moderate-intensity rotating magnetic fields do not affect bone quality and bone remodeling in hindlimb suspended rats.

Abundant evidence has substantiated the positive effects of pulsed electromagnetic fields (PEMF) and static magnetic fields (SMF) on inhibiting osteopenia and promoting fracture healing. However, the osteogenic potential of rotating magnetic fields (RMF), another common electromagnetic application modality, remains poorly characterized thus far, although numerous commercial RMF treatment devices have been available on the market. Herein the impacts of RMF on osteoporotic bone microarchitecture, bone strength and bone metabolism were systematically investigated in hindlimb-unloaded (HU) rats. Thirty two 3-month-old male Sprague-Dawley rats were randomly assigned to the Control (n = 10), HU (n = 10) and HU with RMF exposure (HU+RMF, n = 12) groups. Rats in the HU+RMF group were subjected to daily 2-hour exposure to moderate-intensity RMF (ranging from 0.60 T to 0.38 T) at 7 Hz for 4 weeks. HU caused significant decreases in body mass and soleus muscle mass of rats, which were not obviously altered by RMF. Three-point bending test showed that the mechanical properties of femurs in HU rats, including maximum load, stiffness, energy absorption and elastic modulus were not markedly affected by RMF. µCT analysis demonstrated that 4-week RMF did not significantly prevent HU-induced deterioration of femoral trabecular and cortical bone microarchitecture. Serum biochemical analysis showed that RMF did not significantly change HU-induced decrease in serum bone formation markers and increase in bone resorption markers. Bone histomorphometric analysis further confirmed that RMF showed no impacts on bone remodeling in HU rats, as evidenced by unchanged mineral apposition rate, bone formation rate, osteoblast numbers and osteoclast numbers in cancellous bone. Together, our findings reveal that RMF do not significantly affect bone microstructure, bone mechanical strength and bone remodeling in HU-induced disuse osteoporotic rats. Our study indicates potentially obvious waveform-dependent effects of electromagnetic fields-stimulated osteogenesis, suggesting that RMF, at least in the present form, might not be an optimal modality for inhibiting disuse osteopenia/osteoporosis.

Bone marrow-derived cells and biophysical stimulation for talar osteochondral lesions: a randomized controlled study.

Osteochondral lesions of the talus (OLT) frequently occur after ankle sprains in young patients participating in sports activities. These injuries may lead to chronic pain, joint swelling, and finally osteoarthritis, therefore, surgical repair is frequently needed. A collagen scaffold seeded with bone marrow-derived cells (BMDCs) harvested from patient's iliac crest and implanted into the OLT through a single arthroscopic procedure has been recently proposed as an effective treatment option. Nevertheless, BMDCs, embedded in an inflammatory environment, tend to differentiate toward a fibroblast phenotype with a consequential loss of mechanical characteristics. Biophysical stimulation with pulsed electromagnetic fields (PEMFs) has been shown to promote anabolic chondrocyte activity, stimulate proteoglycan synthesis, and reduce the release of the most relevant pro-inflammatory cytokines. The aim of this randomized controlled trial was to evaluate the effects of PEMFs on clinical outcome in patients who underwent BMDCs transplantation for OLT. Thirty patients affected by grade III and IV Outerbridge OLT underwent BMDCs transplantation. After surgery, patients were randomly assigned to either experimental group (PEMFs 4 hours per day for 60 days starting within 3 days after operation) or control group. Clinical outcome was evaluated with (American Orthopaedic Foot and Ankle Society) AOFAS score, Visual Analog Scale (VAS), and Short Form-36 (SF-36). Significantly higher AOFAS score was recorded in the experimental group both at 6 or 12 months follow-up. At 60 days and 6 and 12 months follow-up, significant lower pain was observed in the experimental group. No significant difference was found in SF-36 between groups. A superior clinical outcome was found in the experimental group with more than 10 points higher AOFAS score at final follow-up. Biophysical stimulation started soon after surgery aided patient recovery leading to pain control and a better clinical outcome with these improvements lasting more than 1 year after surgery. Level II, prospective comparative study.

AB0777 Wearable Pulsed Electromagnetic Fields Device in Knee Osteoarthritis Patients: Preliminary Results of A Double Blinded, Randomized, Placebo Controlled, Clinical Trial

BackgroundKnee osteoarthritis (OA) is the most common form of joint disease and the major cause of pain and physical disability among elderly people. To relieve pain, many patients, in order...

Effects of pulsed electromagnetic fields on the expression of NFATc1 and CAII in mouse osteoclast-like cells.

Pulsed electromagnetic fields (PEMF) have proven to be an effective noninvasive method in the prevention and treatment of osteoporosis. This study evaluated the effects of PEMF on the expression of the NFATc1, CAII and RANK genes in mouse osteoclast-like cells. Bone marrow from bilateral tibiae and femurs was cultured in differentiation medium in the presence of soluble macrophage colony stimulating factor (M-CSF) and receptor activator of nuclear factor kappa-B ligand (RANKL). After 5 days, the osteoclast-like cells were confirmed by both tartrate-resistant acid phosphatase (TRAP) staining and bone resorption assays. The osteoclast-like cells were divided into five groups and exposed to the following treatments for 3days: M-CSF; M-CSF+RANKL; M-CSF+RANKL+osteoprotegerin (OPG), M-CSF+RANKL+premarin (E2); and M-CSF+RANKL+PEMF. The numbers of multinucleated, TRAP-positive osteoclast-like cells and resorption pits formed were determined. The expression of NFATc1, CAII and RANK mRNA was determined with real-time fluorescent quantitative polymerase chain reaction. PEMF substantially reduced the number of osteoclast-like cells in the culture with M-CSF+RANKL. The level of NFATc1, CAII, and RANK mRNA expression was decreased in the M-CSF+RANKL+PEMF group compared to the M-CSF+RANKL group (p=0.007, p=0.039, p=0.001, respectively). The mRNA expression of NFATc1, CAII, and RANK was not higher in the M-CSF+RANKL+OPG group compared to the M-CSF+RANKL+PEMF group (p=0.682, p=0.200, p=0.924, respectively). In addition, there was no difference in the expression of mRNA from NFATc1, CAII, and RANK between the M-CSF+RANKL+PEMF group and the M-CSF+RANKL+E2 group (p=0.853, p=0.509, p=0.664, respectively). These data suggest that PEMF might modulate the process of osteoclastogenesis and subsequent bone resorption, at least partially, through NFATc1, CAII and RANK.

Pulsed Electromagnetic Field Stimulation of Intervertebral Disc Cells

Pulsed electromagnetic field (PEMF) stimulation has been proposed for the noninvasive treatment of a variety of musculoskeletal disorders. PEMF is most commonly applied in the treatment of fracture nonunions or delayed fusion. PEMF stimulation devices are FDA approved as a complimentary therapy and there is clinical evidence of effectiveness for bone stimulation. More recently, potential therapeutic effects of PEMF on muscle and cartilage have been reported, with also an increasing interest in the application for the treatment of disc disorders. We have studied the influence of PEMFs in the mT range on isolated intervertebral disc cells in both 2D monolayer and 3D cell culture models, exploring the influence of parameters such as field strength, pulsing frequency, and daily exposure. Depending on the nature of the PEMF stimulation, we have demonstrated a mild anabolic effect, mostly of mitogenic nature, and also the potential to decrease the expression of catabolic enzymes, including matrix metalloproteinases and aggrecanases. A full and detailed understanding of the pathway(s) by which PEMFs influence cellular metabolism remains the topic of current investigations. Information on the optimal strategy for PEMF stimulation of the IVD is scarce. BMP-2 has been shown to mediate the response of disc cells to PEMF, suggesting a potential benefit of combined therapy. However, in vitro studies have also highlighted the highly variable nature of the response of disc cells to PEMF stimulation. Further work is required to elucidate the optimal parameters for PEMF therapy, to validate the process in vivo before translating the process to clinical practice. Disclosure of Interest None declared

Effects of pulsed electromagnetic fields on homing genes of mouse osteoblasts

Objective To investigate the effects of pulsed electromagnetic fields (PEMF) on homing and proliferation-related genes of mouse osteoblasts.Methods 9 week-old C57BL/6 mice were treated with PEMF (70 Hz,1 mT) for 4～5 weeks,while mice in control group didn't not receive PEMF.Bone marrow cells of femurs and tibias were flushed out,and the bones were minced and incubated at 37 ℃ with a type Ⅰ collagenase.Bone associated mononuclear cells (MNCs) were isolated via density centrifugation with Lymphoprep.Magnetic cell sorting was used before flow-cytometric sorting,and the ALCAM+Sca-1-cells were collected.The homing and proliferation-related genes expressed in ALCAM+Sca-1-cells were detected with high throughput microarray and RT-PCR.Results The expression of Jag1 and Ang-1 in mouse osteoblasts increased under the effects of PEMF.Conclusions PEMF may have regulation effects on HSC (hematopoietic stem cell) survival through modulating the homing and proliferationrelated genes in ALCAM+Sca-1-osteoblasts. Key words: Pulsed electromagnetic fields; Osteoblasts; Stem cell niche

Pulsed Electromagnetic Fields Partially Preserve Bone Mass, Microarchitecture, and Strength by Promoting Bone Formation in Hindlimb-Suspended Rats

A large body of evidence indicates that pulsed electromagnetic fields (PEMF), as a safe and noninvasive method, could promote in vivo and in vitro osteogenesis. Thus far, the effects and underlying mechanisms of PEMF on disuse osteopenia and/or osteoporosis remain poorly understood. Herein, the efficiency of PEMF on osteoporotic bone microarchitecture, bone strength, and bone metabolism, together with its associated signaling pathway mechanism, was systematically investigated in hindlimb-unloaded (HU) rats. Thirty young mature (3-month-old), male Sprague-Dawley rats were equally assigned to control, HU, and HU + PEMF groups. The HU + PEMF group was subjected to daily 2-hour PEMF exposure at 15 Hz, 2.4 mT. After 4 weeks, micro-computed tomography (µCT) results showed that PEMF ameliorated the deterioration of trabecular and cortical bone microarchitecture. Three-point bending test showed that PEMF mitigated HU-induced reduction in femoral mechanical properties, including maximum load, stiffness, and elastic modulus. Moreover, PEMF increased serum bone formation markers, including osteocalcin (OC) and N-terminal propeptide of type 1 procollagen (P1NP); nevertheless, PEMF exerted minor inhibitory effects on bone resorption markers, including C-terminal crosslinked telopeptides of type I collagen (CTX-I) and tartrate-resistant acid phosphatase 5b (TRAcP5b). Bone histomorphometric analysis demonstrated that PEMF increased mineral apposition rate, bone formation rate, and osteoblast numbers in cancellous bone, but PEMF caused no obvious changes on osteoclast numbers. Real-time PCR showed that PEMF promoted tibial gene expressions of Wnt1, LRP5, β-catenin, OPG, and OC, but did not alter RANKL, RANK, or Sost mRNA levels. Moreover, the inhibitory effects of PEMF on disuse-induced osteopenia were further confirmed in 8-month-old mature adult HU rats. Together, these results demonstrate that PEMF alleviated disuse-induced bone loss by promoting skeletal anabolic activities, and imply that PEMF might become a potential biophysical treatment modality for disuse osteoporosis.

Effects of pulsed electromagnetic field therapy on delayed-onset muscle soreness in biceps brachii

to compare the effects of pulsed electromagnetic field (PEMF) therapy and sham treatment on DOMS-related variables in elbow flexors at 24, 48 and 72 h after delayed onset muscle soreness (DOMS) induction exercise. randomized, double-blind, placebo-controlled study. Yonsei University laboratory. In total, 30 healthy male college students. Muscle soreness, peak torque, median frequency (MDF) and electromechanical delay (EMD) during isometric contraction at 24, 48 and 72 h after DOMS induction exercise. Overall, the application of the PEMF was found to be effective in reducing the physiological deficits associated with DOMS, including improved recovery of perceived muscle soreness, MDF, and EMD during isometric contraction. Our results did not show that PEMF treatment was mechanically more effective for isometric peak torque generation compared to the sham group. this study indicates that PEMF may be useful as a modality to reduce DOMS symptoms. However, further well-designed experiments are required to determine optimal treatment dosage and duration, and to investigate the physiological and clinical mechanisms of PEMF on DOMS.

Effect of Pulsed Electromagnetic Field (PEMF) on Infarct Size and Inflammation After Cerebral Ischemia in Mice

Pulsed electromagnetic fields (PEMF) have been demonstrated to have anti-inflammatory and pro-regenerative effects in animals and humans. We used the FDA-approved Sofpulse (Ivivi Health Sciences, LLC) to study effect of PEMF on infarct size and poststroke inflammation following distal middle cerebral artery occlusion (dMCAO) in mice. Electromagnetic field was applied within 30-45 min after ischemic brain damage and utilized twice a day for 21 consecutive days. Ischemic infarct size was assessed using MRI and histological analysis. At 21 days after dMCAO, the infarct size was significantly (by 26%) smaller in PEMF-treated animals as compared to controls. Neuroinflammation in these animals was evaluated using specialized cytokine/chemokine PCR array. We demonstrate that PEMF significantly influenced expression profile of pro- and anti-inflammatory factors in the hemisphere ipsilateral to ischemic damage. Importantly, expression of gene encoding major pro-inflammatory cytokine IL-1α was significantly reduced, while expression of major anti-inflammatory IL-10 was significantly increased. PEMF application significantly downregulated genes encoding members of the major pro-apoptotic tumor necrosis factor (TNF) superfamily indicating that the treatment could have both anti-inflammatory and anti-apoptotic effects. Both reduction of infarct size and influence on neuroinflammation could have a potentially important positive impact on the poststroke recovery process, implicating PEMF as a possible adjunctive therapy for stroke patients.

Pulsed electromagnetic fields potentiate neurite outgrowth in the dopaminergic MN9D cell line

Pulsed electromagnetic fields (PEMF) exert biological effects and are in clinical use to facilitate bone repair and wound healing. Research has demonstrated that PEMF can induce signaling molecules and growth factors, molecules that play important roles in neuronal differentiation. Here, we tested the effects of a low-amplitude, nonthermal, pulsed radiofrequency signal on morphological neuronal differentiation in MN9D, a dopaminergic cell line. Cells were plated in medium with 10% fetal calf serum. After 1 day, medium was replaced with serum-containing medium, serum-free medium, or medium supplemented with dibutyryl cyclic adenosine monophosphate (Bt2 cAMP), a cAMP analog known to induce neurite outgrowth. Cultures were divided into groups and treated with PEMF signals for either 30 min per day or continuously for 15 min every hour for 3 days. Both serum withdrawal and Bt2 cAMP significantly increased neurite length. PEMF treatment similarly increased neurite length under both serum-free and serum-supplemented conditions, although to a lesser degree in the presence of serum, when continuous treatments had greater effects. PEMF signals also increased cell body width, indicating neuronal maturation, and decreased protein content, suggesting that this treatment was antimitotic, an effect reversed by the inhibitor of cAMP formation dideoxyadenosine. Bt2 cAMP and PEMF effects were not additive, suggesting that neurite elongation was achieved through a common pathway. PEMF signals increased cAMP levels from 3 to 5 hr after treatment, supporting this mechanism of action. Although neuritogenesis is considered a developmental process, it may also represent the plasticity required to form and maintain synaptic connections throughout life.

In vivo effect of two different pulsed electromagnetic field frequencies on osteoarthritis

Osteoarthritis (OA) is a joint pathology characterized by fibrillation, reduced cartilage thickness and subchondral bone sclerosis. There is evidence that pulsed electromagnetic fields (PEMFs) counteract OA progression, but the effect of two different PEMF frequencies has not yet been shown. The aim of this study was to test the effectiveness of PEMFs at two different frequencies (37 and 75 Hz) in a late OA stage in 21-month-old Guinea pigs. After 3 months of 6 h/day PEMF stimulation, histological and histomorphometric analyses of the knees were performed. At both frequencies, PEMFs significantly reduced histological cartilage score, fibrillation index (FI), subchondral bone thickness (SBT) and trabecular number (Tb.N) and increased trabecular thickness (Tb.Th) and separation (Tb.Sp) in comparison to the not treated SHAM group. However, PEMFs at 75 Hz produced significantly more beneficial effects on the histological score and FI than 37 Hz PEMFs. At 75 Hz, PEMFs counteracted cartilage thinning as demonstrated by a significantly higher cartilage thickness values than either those of the SHAM or 37 Hz PEMF-treated groups. Although in severe OA both PEMF frequencies were able to limit its progression, 75 Hz PEMF stimulation achieved the better results.

Abstract W P197: Pulsed Electromagnetic Field Attenuates High Intracranial Pressure Induced Microvascular Shunting in Rats

Introduction: We previously reported that high intracranial pressure (ICP) in rats caused a transition from capillary (CAP) to non-nutritive microvascular shunt (MVS) flow associated with tissue hypoxia and increased blood brain barrier (BBB) permeability. We also showed that pulsed electromagnetic field (PEMF) increases blood flow velocity and tissue oxygenation in the normal rat brain. We hypothesized that PEMF attenuates the detrimental effects of non-nutritive MVS flow induced by high ICP. Methods: Using in vivo 2-photon laser scanning microscopy (2PLSM) over the rat parietal cortex, we studied the effects of PEMF on microvascular blood flow velocity, tissue oxygenation (NADH) and BBB permeability (dye extravasation) before and during 4 hours of elevated ICP. Doppler cortical flow, rectal and cranial temperatures, intracranial and arterial pressures, blood gases and electrolytes were monitored. After baseline imaging at normal ICP (10 mmHg), rats were subjected to intracranial hypertension (30 mmHg) by raising an artificial cerebrospinal fluid reservoir connected to a catheter in the cisterna magna. After control recording at high ICP of 30 mmHg, PEMF was applied for 30 min and imaging was continuously performed for up to 4 hours after the treatment. In control animals PEMF was not applied. Results: PEMF treatment reduced tissue hypoxia as reflected by a decrease in NADH by 14.6±3.7% (n=7 rats per group, mean ± SEM, p&lt;0.05). BBB permeability was also reduced as reflected by reduction of dye extravasation by 17.2±5.4% (p&lt;0.05). This effect was consistent with dilation of arterioles (+4.5±3.2%) and an increase in capillary blood flow velocity (+4.7±3.2%). PEMF did not completely mitigated the gradual increase in MVS flow at high ICP but, as reflected by MVS/capillary ratio, the transition to non-nutritive flow over 4 hours was less steep in the PEMF treated rats compared to the untreated (2.3±1.1 and 3.8±2.1% change per hour, respectively, p&lt;0.05). Conclusions: PEMF reduces tissue hypoxia and BBB degradation by modulating cerebral blood flow topography at intracranial hypertension in a rat brain. PEMF could be an effective treatment for intracranial hypertension after severe cerebral insults.

Pulsed electromagnetic fields protect the balance between adipogenesis and osteogenesis on steroid‐induced osteonecrosis of femoral head at the pre‐collapse stage in rats

This study was designed to investigate the effects of pulsed electromagnetic fields (PEMF) on the balance of adipogenesis and osteogenesis on steroid-induced osteonecrosis of the femoral head (OFH) in rats. Forty-two rats were divided into three groups: Steroid group (S, n = 16); Steroid + PEMF group (S + P, n = 16); and Control group (C, n = 10). For groups S and S + P, all rats were first intravenously given 10 µg/kg lipopolysaccharide on day 1, and then intramuscularly injected with 20 mg/kg methylprednisolone acetate on days 2, 3, and 4, with an interval of 24 h. After 4 weeks, the S + P group was treated with PEMF (4.5-ms square pulse, repeated at 15 Hz, with a peak of 1.2 mT) for 4 h a day for the next 8 weeks. Group S was not exposed to PEMF. Group C was chosen as the control group, without steroid use and exposure to PEMF. After 8 weeks of treatment, the histological changes, and mRNA and protein expressions of PPAR-γ2 and Runx2 were measured and analyzed. Compared with the S group, lower incidence of osteonecrosis (31% vs. 69%, P < 0.05) and empty osteocyte lacuna rate (36.16 ± 15.34 vs. 59.55 ± 21.70, P < 0.01) was observed in the S + P group. Furthermore, PEMF suppressed the expressions of PPAR-γ2 and improved the expressions of Runx2 in the femoral head (P < 0.05). All data suggest that PEMF is an effective physiotherapy in the treatment of steroid-induced ONFH, and the possible underlying mechanisms include protecting the balance between adipogenesis and osteogenesis.

Pulsed electromagnetic fields (PEMF) promote early wound healing and myofibroblast proliferation in diabetic rats

Reduced collagen deposition possibly leads to slow recovery of tensile strength in the healing process of diabetic cutaneous wounds. Myofibroblasts are transiently present during wound healing and play a key role in wound closure and collagen synthesis. Pulsed electromagnetic fields (PEMF) have been shown to enhance the tensile strength of diabetic wounds. In this study, we examined the effect of PEMF on wound closure and the presence of myofibroblasts in Sprague-Dawley rats after diabetic induction using streptozotocin. A full-thickness square-shaped dermal wound (2 cm × 2 cm) was excised aseptically on the shaved dorsum. The rats were randomly divided into PEMF-treated (5 mT, 25 Hz, 1 h daily) and control groups. The results indicated that there were no significant differences between the groups in blood glucose level and body weight. However, PEMF treatment significantly enhanced wound closure (days 10 and 14 post-wounding) and re-epithelialization (day 10 post-wounding), although these improvements were no longer observed at later stages of the wound healing process. Using immunohistochemistry against α-smooth muscle actin (α-SMA), we demonstrated that significantly more myofibroblasts were detected on days 7 and 10 post-wounding in the PEMF group when compared to the control group. We hypothesized that PEMF would increase the myofibroblast population, contributing to wound closure during diabetic wound healing.