Effects Of Electromagnetic Stimulation Research Articles

Alleviation of Stress-Induced Damage to Rat Brain Cells by Transcranial Electromagnetic Stimulation

The effect of transcranial electromagnetic stimulation on immobilization stress-induced damage to rat brain cells was studied. Electromagnetic stimulation was performed by microwave (λ = 5.6 mm) electromagnetic radiation with a power density of 0.67, 1.3, and 2.0 W/cm2 modulated by low-frequency pulses with a repetition rate of 78 Hz. A statistically significant blocking effect of electromagnetic stimulation on the process of stress-induced damage to brain cells (neurons) was detected in all three cases as the state of the neural network cells before and after stress exposure was compared. The most pronounced anti-stress effect was observed when electromagnetic stimulation with a power of 1.3 W/cm2 was used. A biophysical model of the anti-stress effect is proposed: according to the model, microwave radiation causes a globule–tangle phase transition in albumin, the major protein of the cerebrospinal fluid, and the tryptophan molecule fixed inside the globule is released. Free tryptophan enters the brain with the cerebrospinal fluid flow and enhances serotonin production, which blocks the stress effect, in the neural network of the brain.

Model of Murine Ventricular Cardiac Tissue for In Vitro Kinematic-Dynamic Studies of Electromagnetic and β-Adrenergic Stimulation.

In a model of murine ventricular cardiac tissue in vitro, we have studied the inotropic effects of electromagnetic stimulation (frequency, 75 Hz), isoproterenol administration (10 μM), and their combination. In particular, we have performed an image processing analysis to evaluate the kinematics and the dynamics of beating cardiac syncytia starting from the video registration of their contraction movement. We have found that the electromagnetic stimulation is able to counteract the β-adrenergic effect of isoproterenol and to elicit an antihypertrophic response.

Effects of Electromagnetic Stimulation on Gene Expression of Mesenchymal Stem Cells and Repair of Bone Lesions.

Most people experience bone damage and bone disorders during their lifetimes. The use of autografts is a suitable way for injury recovery and healing. Mesenchymal stem cells (MSCs) are key players in tissue engineering and regenerative medicine. Their proliferation potential and multipotent differentiation ability enable MSCs to be considered as appropriate cells for therapy and clinical applications. Differentiation of stem cells depends on their microenvironment and biophysical stimulations. The aim of this study is to analyze the effects of an electromagnetic field on osteogenic differentiation of stem cells. In this experimental animal study, we assessed the effects of the essential parameters of a pulsatile electromagnetic field on osteogenic differentiation. The main purpose was to identify an optimum electromagnetic field for osteogenesis induction. After isolating MSCs from male Wistar rats, passage-3 (P3) cells were exposed to an electromagnetic field that had an intensity of 0.2 millitesla (mT) and frequency of 15 Hz for 10 days. Flow cytometry analysis confirmed the mesenchymal identity of the isolated cells. Pulsatile electromagnetic field-stimulated cells were examined by immunocytochemistry and real-time polymerase chain reaction (PCR). Electromagnetic field stimulation alone motivated the expression of osteogenic genes. This stimulation was more effective when combined with osteogenic differentiation medium 6 hours per day for 10 days. For the in vivo study, an incision was made in the cranium of each animal, after which we implanted a collagen scaffold seeded with stimulated cells into the animals. Histological analysis revealed bone formation after 10 weeks of implantation. We have shown that the combined use of chemical factors and an electromagnetic field was more effective for inducing osteogenesis. These elements have synergistic effects and are beneficial for bone tissue engineering applications.

Choice of osteoblast model critical for studying the effects of electromagnetic stimulation on osteogenesis in vitro

ABSTRACTThe clinical benefits of electromagnetic field (EMF) therapy in enhancing osteogenesis have been acknowledged for decades, but agreement regarding the underlying mechanisms continues to be sought. Studies have shown EMFs to promote osteoblast-like cell proliferation, or contrarily, to induce differentiation and enhance mineralization. Typically these disparities have been attributed to methodological differences. The present paper argues the possibility that the chosen osteoblast model impacts stimulation outcome. Phenotypically immature cells, particularly at low seeding densities, appear to be prone to EMF-amplified proliferation. Conversely, mature cells at higher densities seem to be predisposed to earlier onset differentiation and mineralization. This suggests that EMFs augment ongoing processes in cell populations. To test this hypothesis, mature SaOS-2 cells and immature MC3T3-E1 cells at various densities, with or without osteo-induction, were exposed to sinusoidal 50 Hz EMF. The exposure stimulated the proliferation of MC3T3-E1 and inhibited the proliferation of SaOS-2 cells. Baseline alkaline phosphatase (ALP) expression of SaOS-2 cells was high and rapidly further increased with EMF exposure, whereas ALP effects in MC3T3-E1 cells were not seen until the second week. Thus both cell types responded differently to EMF stimulation, corroborating the hypothesis that the phenotypic maturity and culture stage of cells influence stimulation outcome.

Effect of electromagnetic stimulation on hydraulic conductivity

Hydraulic conductivity is a measure of the rate at which water flows through porous media. In this study, the effect of radiofrequency (RF) waves on hydraulic conductivity was investigated. Bentonite clay was tested in rigid-wall, cylindrical permeameters and stimulated using monopole antenna. Falling-head tests were performed to measure the hydraulic conductivity of the clay and sand samples, respectively. Using RF frequencies of 80, 94 and 153 MHz, flow through the clay sample was sharply decreased for a relatively short period of time and then stabilised at a higher hydraulic conductivity. The test was replicated with a decrease of the input RF power from 30 to 20 W, and then to 10 W. The results revealed that the change in the hydraulic conductivity was larger at the higher input RF power. Measurements of the electric field component of RF waves were performed to map the electric field. In addition, the electric field was simulated using COMSOL Multiphysics for better three-dimensional visualisation and analysis. The possibility of a dielectrophoretic phenomenon governing this effect was studied for the simulated data. The result was in agreement with the results from the experimental field investigation.

Effects of Electromagnetic Stimulation on Calcified Matrix Production by SAOS-2 Cells over a Polyurethane Porous Scaffold

Effects of Electromagnetic Stimulation on Calcified Matrix Production by SAOS-2 Cells over a Polyurethane Porous Scaffold

Effects of electromagnetic stimulation on neurogenesis and neuronal proliferation in rat hippocampal slice culture

Purpose:Transcranial electromagnetic stimulation(TMS) is a noninvasive method which stimulates the central nervous system through pulsed magnetic fields without direct effect on the neurons. Although the neurobiologic mechanisms of magnetic stimulation are unknown, the effects on the brain are variable according to the diverse stimulation protocols. This study aims to observe the effect of the magnetic stimulation with two different stimulation methods on the cultured hippocampal slices. Methods:We obtained brains from 8-days-old Spague-Dawley rats and dissected the hippocampal tissue under the microscope. Then we chopped the tissue into 450 µm thickness slices and cultured the hippocampal tissue by Stoppini's method. We divided the inserts, which contained five healthy cultured hippocampal slices respectively, into magnetic stimulation groups and a control group. To compare the different effects according to the frequency of magnetic stimulation, stimulation was done every three days from five days in vitro at 0.67 Hz in the low stimulation group and at 50 Hz in the high stimulation group. After N-methyl-D-aspartate exposure to the hippocampal slices at 14 days in vitro, magnetic stimulation was done every three days in one and was not done in another group. To evaluate the neuronal activity after magnetic stimulation, the NeuN/β-actin ratio was calculated after western blotting in each group. Results:The expression of NeuN in the magnetic stimulation group was stronger than that of the control group, especially in the high frequency stimulation group. After N-methyl-D-aspartate exposure to hippocampal slices, the expression of NeuN in the magnetic stimulation group was similar to that of the control group, whereas the expression in the magnetic non-stimulation group was lower than that of the control group. Conclusion:We suggest that magnetic stimulation increases the neuronal activity in cultured hippocamal slices, in proportion to the stimulating frequency, and has a neuroprotective effect on neuronal damage.

Effects of electromagnetic stimulation on the functional responsiveness of isolated rat osteoclasts.

We report the effects of pulsed electromagnetic fields (PEMFs) on the responsiveness of osteoclasts to cellular, hormonal, and ionic signals. Osteoclasts isolated from neonatal rat long bones were dispersed onto either slices of devitalised cortical bone (for the measurement of resorptive activity) or glass coverslips (for the determination of the cytosolic free Ca2+ concentration, [Ca2+]). Osteoclasts were also cocultured on bone with osteoblastlike, UMR-106 cells. Bone resorption was quantitated by scanning electron microscopy and computer-assisted morphometry. PEMF application to osteoblast-osteoclast cocultures for 18 hr resulted in a twofold stimulation of bone resorption. In contrast, resorption by isolated osteoclasts remained unchanged in the presence of PEMFs, suggesting that osteoblasts were necessary for the PEMF-induced resorption simulation seen in osteoblast-osteoclast cocultures. Furthermore, the potent inhibitory action of the hormone calcitonin on bone resorption was unaffected by PEMF application. However, PEMFs completely reversed another quite distinct action of calcitonin on the osteoclast: its potent inhibitory effect on the activation of the divalent cation-sensing (or Ca2+) receptor. For these experiments, we made fura 2-based measurements of cytosolic [Ca2+] in single osteoclasts in response to the application of a known Ca2+ receptor agonist, Ni2+. We first confirmed that activation of the osteoclast Ca2+ receptor by Ni2+ (5 mM) resulted in a characteristic monophasic elevation of cytosolic [Ca2+]. As shown previously, this response was attenuated strongly by calcitonin at concentrations between 0.03 and 3 nM but remained intact in response to PEMFs. PEMF application, however, prevented the inhibitory effect of calcitonin on Ni2+-induced cytosolic Ca2+ elevation. This suggested that the fields disrupted the interaction between the calcitonin and Ca2+ receptor systems. In conclusion, we have shown that electromagnetic fields stimulate bone resorption through an action on the osteoblast and, by abolishing the inhibitory effects of calcitonin, also restore the responsiveness of osteoclasts to divalent cations.

Effect of electromagnetic stimulation with different waveforms on cultured chick tendon fibroblasts

An energy efficient electromagnetic stimulator device for fracture healing was compared to a commercially available device in stimulating cell growth in tissue cultures. The energy efficient device, which conserves energy by using a bidirectional time-dependent magnetic wave form, and the commercially available stimulator, which uses a unidirectional time-dependent magnetic wave form, were tested on chick tendon fibroblasts in primary culture. Comparing non-stimulated control and cells electromagnetically stimulated with unidirectional and bidirectional waveforms showed that at the growth phase between days 2 and 3, both electrical stimulation techniques increased cell division as measured by DNA synthesis. When cells were dividing rapidly, collagen synthesis was reduced. When the cells reached the confluence there was no difference among the groups (control, unidirectionally stimulated, and bidirectionally stimulated) in terms of number of cells or collagen produced.

Effect of Electromagnetic Stimulation on Patients Suffering from Non-Union. A Retrospective Study with a Control Group

In this study we have reviewed a group of patients suffering from non-union treated at the same hospitals by the same surgeons. Twenty six patients (control group) received an orthopaedic treatment aimed at promoting bone healing, fourty one patients (experimental group) were stimulated with an electromagnetic field generator without any further change in the orthopaedic management of the non-union. Eighteen patients healed in the control group and thirty six in the experimental group. The average healing time was shorter among patients stimulated. No difference was observed in the success rate between the 2 groups of patients for non infected non-unions. Infection proved to be detrimental for the success of the treatment in the control group, while it did not negatively influence the outcome of stimulation. Provided that the orthopaedic treatment of the non-union is considered satisfactory, electromagnetic stimulation is a valid option in the treatment of non-unions.

Electromagnetic stimulation blocks isometric twitch contraction in the frog sciatic nerve - gastrocnemius muscle preparation

The effect of electromagnetic stimulation (EMS) on nerve conduction and muscle twitch contraction was studied in isolated sciatic nerve-gastrocnemius muscle of the frog. Electrical stimulation (ES) of the sciatic nerve produced twitch contractions in the gastrocnemius muscle and these responses were reduced and eventually blocked by EMS, applied to the nerve simultaneously with ES, from a d.c. source at a certain frequency and duration of the induced current. The EMS- induced inhibition of the twitch contractions was reversible, and this depended on the induced current and its duration. The possibility that other factors may have contributed to the inhibition of twitch contractions, such as a rise in temperature, was also investigated. It was concluded that EMS inhibited indirectly- elicited twitch contractions produced by ES in the frog nerve- muscle preparation.

Electromagnetic Stimulation of Ligament Healing in Rabbits

To evaluate the effect of a specific noninvasive method of electrical stimulation on ligament healing in rabbits, a solid core electromagnet energized by a square wave unidirectional current was applied to injured and repaired medial collateral ligaments seven hours per day, five days per week for intervals of up to six weeks. Healing was evaluated by gross, histologic, biochemical, and biomechanical parameters. Stimulation was shown to increase histologic maturity relatively, restore stiffness and failure strength earlier, and return collagen content toward normal unoperated values sooner in these healing ligaments. It is uncertain whether the end point of healing is affected by this technique, but at six weeks both histologic and biochemical evidence of acceleration remains. Further investigation into the effect of electromagnetic stimulation by this and other fields on non-osseous tissues and their components is indicated.

Morphological effect of electromagnetic stimulation on the skeleton of new born mouse

Morphological effect of electromagnetic stimulation on the skeleton of new born mouse