Low‑frequency pulsed electromagnetic field promotes functional recovery, reduces inflammation and oxidative stress, and enhances HSP70 expression following spinal cord injury

Positive effects of pulsed electromagnetic fields on behavior, immune function, and oxidative and inflammatory state in old mice

The establishment of chronic oxidative and inflammatory stress with aging leads to the deterioration of the nervous and immune systems and, consequently, to the loss of health. The aim of this work was to study the effect of exposure to low-frequency pulsed electromagnetic fields (PEMFs) produced by the NEURALTER® system (15 min/day for 4 weeks) in the behavior, immune functions, and oxidative and inflammatory state of old mice. Female old CD1 mice were divided into three groups: control group, handling control group and Neuralter group. Then, behavioral tests were performed, and peritoneal leukocytes were extracted to analyze function, oxidative and inflammatory parameters. In peritoneal leukocytes from old mice, the effects in vitro of 15 min with NEURALTER® were studied on function and oxidative parameters. The results show that after this type of treatment, old mice had greater coordination and locomotion, better immune function, and an oxidative-inflammatory state. Similarly, the immune function and oxidative state of leukocytes showed an improvement when these cells were exposed directly to the NEURALTER® system. In conclusion, the exposure to low-frequency PEMFs produced by the NEURALTER® system has beneficial effects on health in aging. In addition, this effect is direct, at least in part, on immune cells.

Effect of 50-Hz magnetic fields on the expression of activation-induced deaminase, B-cell lymphoma 6 and serum levels of interleukin-6, interleukin-21

BACKGROUND

Investigations showed different effects of magnetic fields (MFs) on the immune system. During humoral immune responses, genes of activation-induced deaminase (AID) and B-cell lymphoma-6 (Bcl-6) are expressed and interleukin (IL)-6 and IL-21 are produced. These factors play significant roles in class switching, affinity maturation of antibodies and activations of B cells germinal centers (GCs). Therefore, this study investigated the effect of 50-Hz MFs exposure with different densities on these factors.

MATERIALS AND METHODS

Eighty rats were divided into four exposures and control groups. The treatment groups were exposed to magnetic flux densities of 1, 100, 500, and 2000 μT (50 Hz, 2 h/d for 60 d). To activation of the immune system, all the animals were immunized with human serum albumin on days 31, 44, and 58 of exposure. Reverse transcription-quantitative polymerase chain reaction was used to assay the expression levels of AID and Bcl-6 genes in the spleen. The serum levels of IL-6 and IL-21 were also detected by enzyme-linked immunosorbent assay at the pre-and post-immunization phases.

RESULTS

AID expression was significantly declined at 1μT magnetic flux density, while no change was observed in the expression of Bcl-6. Serum IL-6 was increased only in the 500 μT group at the post-immunization phase.

CONCLUSIONS

It seems exposure to 50-Hz MFs at 1 μT density, suppresses AID and may cause a decline in class switching and affinity maturation of Abs. On the other hand, exposure to 500 μT, may activate them. These findings demonstrate the various potential effects of MFs on the humoral immune system.

Physalis pubescens L. alleviates testicular disruptions associated with streptozotocin-induced diabetes in male Wistar rats, Rattus norvegicus

Testicular impairment is a serious complication of diabetes that is mediated by oxidative stress and inflammation. Physalis has antioxidative and anti-inflammatory actions. Thus, the present study investigated the ameliorative role of Physalis juice (PJ) prepared from the fruits against testicular damages in streptozotocin (STZ)-induced diabetic rats. Adult male Wistar rats were divided randomly into five groups (n=6): control, orally administered 5 mL PJ/kg daily (PJ), injected intraperitoneally with a single dose of 55 mg STZ/kg without treatment (STZ), or treated daily with PJ (STZ+PJ) or with 500 mg metformin/kg (STZ+Met), for 28 days. The STZ group showed a marked elevation in the blood glucose level by 230%, whereas remarkable declines in the serum levels of testosterone (44%), follicle-stimulating hormone (FSH) (48%), and luteinizing hormone (LH) (36%), as compared to controls. In comparison to controls, the testis of the STZ group showed remarkable declines in the testis weight (15%), the glutathione (GSH) content (45%), mRNA and protein levels of B-cell lymphoma-2 (Bcl-2) (48 and 35%), mRNA and activities of superoxide dismutase (SOD) (63 and 40%), catalase (CAT) (56 and 31%), glutathione peroxidase (GPx) (51 and 44%), and glutathione reductase (GR) (62 and 43%), whereas marked elevations in the levels of interleukin-1 beta (IL-1β (169%), tumor necrosis factor-alfa (TNFα) (85%), nitric oxide (NO) (96%), malondialdehyde (MDA) (83%), mRNA and protein levels of Bcl-2-associated X protein (Bax) (400 and 61%), and mRNA level of caspase-3 (Cas-3) (370%). Some histopathological alterations were observed in the testicular tissue of the STZ group. In contrast, PJ markedly alleviated all the abovementioned disturbances. In conclusion, PJ at a dose of 5 mL/kg attenuated the diabetes-associated testicular impairments, which may be due to its antioxidative, anti-inflammatory, and antiapoptotic actions.

Electromagnetic Field Stimulation Attenuates Phasic Nociception after Complete Spinal Cord Injury in Rats

Traumatic spinal cord injury (SCI) is one of the most incapacitating pathologies, leading to huge rehabilitation challenges besides a social-economic burden on SCI patients and their families. There is no complete curative treatment available so far. Non-invasive and patient-friendly use of extremely low-frequency electromagnetic field stimulation (EMF) has emerged as a therapeutic and rehabilitation option. In this study, we tested whole-body EMF stimulation on thoracic complete SCI-induced nociception including sensorimotor deficits in rats. The EMF application significantly attenuated hyperalgesia and allodynia to thermal, electrical, and chemical stimuli from 6 weeks onwards as well as restoration of spinal reflexes, viz., H-reflex and nociceptive flexion reflex at the study endpoint (week 8). Besides, massively increased glutamate at the SCI injury site was observed in SCI rats with no treatment, which was also attenuated significantly by EMF stimulation. Spinal cord histology of the injury area showed a decrease in lesion volume and glial population in the EMF-stimulated rats. These findings indicate the beneficial role of EMF stimulation after thoracic complete SCI in adult male rats and, thereby, a beneficial patient-friendly rehabilitation tool.

Short and long-term effect of reproduction on mitochondrial dynamics and autophagy in rats

We evaluated mitochondrial dynamics and autophagy by investigating the acute and long-term changes in the liver and skeletal muscle of rats in multiple reproductive stages. A total of 48 rats were used. Rats were randomly assigned to three groups (n = 16 per group): nonreproductive females; females that became pregnant, gave birth, but had their pups removed at birth, and thus, did not lactate; and females that experienced pregnancy, gave birth, and were allowed to lactate. Each group was further divided into two-time subgroups (n = 8 per subgroup) and data were collected at a time-point corresponding to 1) peak lactation (day 14 of lactation) in the lactating animals (4 months of age) and 2) 15 weeks after parturition (12 weeks post-weaning in lactating animals; 7 months of age). Levels of several proteins involved in mitochondrial dynamics and the autophagy system were measured in the liver and skeletal muscle. Beclin1 protein levels in the liver were higher in non-lactating rats two weeks after parturition, while Beclin1 protein levels were highest in 7-month-old animals that had previously experienced a standard reproductive event that included pregnancy and a full 3 week of lactation. These animals also exhibited higher protein levels of the mitochondrial fusion marker Mfn2 in the liver. In skeletal muscle, we also observed increased protein levels of the mitochondrial fission marker DRP1 in non-lactating animals compared to animals that lactated. In summary, our data provide insightful information on the mechanisms that influence liver and skeletal muscle remodeling in response to the metabolic challenges of reproduction, and lactation in particular. Autophagy remodeling and mitochondrial fusion seem to coincide with liver mass size during the lactation stage of reproduction. Our findings highlight the complex changes that occur in the liver and skeletal muscle during reproduction, and highlights the remarkable plasticity required during this demanding metabolic feat.

Effect of extremely low frequency magnetic fields on oxidative balance in rat brains subjected to an experimental model of chronic unpredictable mild stress

Background

There has been an increasing interest in researching on the effects of extremely low-frequency magnetic fields on living systems. The mechanism of action of extremely low-frequency magnetic fields on organisms has not been established. One of the hypotheses is related to induce changes in oxidative balance. In this study, we measured the effects of chronic unpredictable mild stress induced-oxidative balance of rat’s brain exposed to extremely low-frequency magnetic fields.

Methods

A first experiment was conducted to find out if 14 days of chronic unpredictable mild stress caused oxidative unbalance in male Wistar rat’s brain. Catalase activity, reduced glutathione concentration, and lipoperoxidation were measured in cerebrum and cerebellum. In the second experiment, we investigate the effects of 7 days extremely low-frequency magnetic fields exposure on animals stressed and unstressed.

Results

The main results obtained were a significant increase in the catalase activity and reduced glutathione concentration on the cerebrum of animals where the chronic unpredictable mild stress were suspended at day 14 and then exposed 7 days to extremely low-frequency magnetic fields. Interestingly, the same treatment decreases the lipoperoxidation in the cerebrum. The stressed animals that received concomitant extremely low frequency magnetic fields exposure showed an oxidative status like stressed animals by 21 days. Thus, no changes were observed on the chronic unpredictable mild stress induced-oxidative damage in the rat’s cerebrum by the extremely low-frequency magnetic field exposure together with chronic unpredictable mild stress.

Conclusions

The extremely low-frequency electromagnetic field exposure can partially restore the cerebrum antioxidant system of previously stressed animals.

The ameliorative role of Physalis pubescens L. against neurological impairment associated with streptozotocin induced diabetes in rats

Neuropathy is considered a critical complication of diabetes mellitus (DM). Scientific studies are needed to relieve these painful complications. The current study aims to estimate the ameliorative role of Physalis juice (PJ) against neurological impairment in streptozotocin (STZ)-induced diabetic rats. Type 1 DM was induced after one week of injecting rats with 55 mg STZ/kg body weight. PJ-treated rats were orally administered 5 ml PJ/kg body weight per day for 28 days after induction of diabetes. A small piece of the cerebral cortex of rats was fixed and used for histopathological investigations. The remaining portion of the cerebral cortex was homogenized for biochemical and molecular analyses. As compared to the controls, STZ-injected rats showed significant elevations in the levels of blood glucose, tumor necrosis factor alfa, interleukin-1β, malondialdehyde, nitric oxide, and expression levels of caspase-3 and B-cell lymphoma-2 associated X-protein. Additionally, remarkable declines in the levels of brain-derived neurotrophic factor, monoamines, B-cell lymphoma-2, glutathione, as well as the activities and gene expression levels of superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase in STZ-treated rats were reported. Moreover, some histopathological alterations were observed in the brain cortex of the STZ-treated rats. On the other hand, the administration of PJ substantially reduced the blood glucose and alleviated the above-mentioned alterations in all the studied parameters of the cerebral cortex. In conclusion, an oral administration of 5 ml PJ/kg revealed a neuroprotective action against neurodegenerative diabetes-induced complications in rats, which might be due to the reported antioxidative and anti-inflammatory actions of PJ. Thus, further therapeutic studies are recommended to apply PJ in the treatment regimen of diabetes.

Pulsed Electromagnetic Field Stimulators Efficacy for Noninvasive Bone Growth in Spine Surgery

The growth of pulsed electromagnetic field (PEMF) therapy and its progress over the years for use in post-operative bone growth has been revolutionary in its effect on bone tissue proliferation and vascular flow. However, further progress in PEMF therapy has been difficult due to lack of more evidence-based understanding of its mechanism of action. Our objective was to review the current understanding of bone growth physiology, the mechanism of PEMF therapy action along with its application in spinal surgery and associated outcomes. The authors of this review examined multiple controlled, comparative, and cohort studies to compare fusion rates of patients undergoing PEMF stimulation. Examining spinal fusion rates, a rounded comparison of post-fusion outcomes with and without bone stimulator was performed. Results showed that postoperative spinal surgery PEMF stimulation had higher rates of fusion than control groups. Though PEMF therapy was proven more effective, multiple factors contributed to difficulty in patient compliance for use. Extended timeframe of treatment and cost of treatment were the main obstacles to full compliance. This review showed that PEMF therapy presented an increased rate of recovery in patients, supporting the use of these devices as an effective post-surgical aid. Given the recent advances in the development of PEMF devices, affordability and access will be much easier suited to the patient population, allowing for more readily available treatment options.

Pulsed-electromagnetic-field induced osteoblast differentiation requires activation of genes downstream of adenosine receptors A2A and A3

Pulsed-electromagnetic-field (PEMF) treatment was found to enhance cellular differentiation of the mouse preosteoblast, MC3T3-E1, to a more osteoblastic phenotype. Differentiation genes such as Alp, BSPI, cFos, Ibsp, Osteocalcin, Pthr1 and Runx2 showed increased expression in response to PEMF stimulation. Detailed molecular mechanisms linking PEMF to the activation of these genes are limited. Two adenosine receptors known to be modulated in response to PEMF, Adora2A and Adora3, were functionally impaired by CRISPR-Cas9-mediated gene disruption, and the consequences of which were studied in the context of PEMF-mediated osteoblastic differentiation. Disruption of Adora2A resulted in a delay of Alp mRNA expression, but not alkaline phosphatase protein expression, which was similar to that found in wild type cells. However, Adora3 disruption resulted in significantly reduced responses at both the alkaline phosphatase mRNA and protein levels throughout the PEMF stimulation period. Defects observed in response to PEMF were mirrored using a chemically defined growth and differentiation-inducing media (DM). Moreover, in cells with Adora2A disruption, gene expression profiles showed a blunted response in cFos and Pthr1 to PEMF treatment; whereas cells with Adora3 disruption had mostly blunted responses in AlpI, BSPI, Ibsp, Osteocalcin and Sp7 gene activation. To demonstrate specificity for Adora3 function, the Adora3 open reading frame was inserted into the ROSA26 locus in Adora3 disrupted cells culminating in rescued PEMF responsiveness and thereby eliminating the possibility of off-target effects. These results lead us to propose that there are complementary and parallel positive roles for adenosine receptor A_2A and A₃ in PEMF-mediated osteoblast differentiation.

HSP70 alleviates spinal cord injury by activating the NF-kB pathway

OBJECTIVES

Spinal cord injury (SCI) is an acute traumatic lesion of neurons in the spinal cord which has a high prevalence in the world, and has no effective surgical treatment. HSP70 is a molecular chaperone protein, serves a protective role in several different models of nervous system injury. The aim of the present study was to investigate the anti-inflammatory role of HSP70 in spinal cord injury and explore its mechanism.

METHODS

In vivo and in vitro models were constructed to mimic SCI. The Basso Mouse Scale (BMS) was applied to assess SCI degrees of the mouse model. Immunofluorescence (IF) was used for visualizing HSP70 and Iba1 in the spinal cord. Western blot assay was employed to quantify HSP70 and p65, and ELISA was for IL-1β and TNF-α.

RESULTS

The results showed that HSP70 expression decreased after SCI. HSP70 and Iba1 showed a decrease of co-localization in SCI mice. Further studies revealed that p65 was upregulated during the process of SCI. Overexpression of HSP70 inhibited the expression of p65 both in vitro and in vivo, and promoted the recovery of SCI mice.

CONCLUSIONS

HSP70 was involved in the pathological process of spinal cord injury, HSP70 alleviated the spinal cord injury via inhibiting NF-κB signaling pathway.

Pulsed electromagnetic fields improve the healing process of Achilles tendinopathy: a pilot study in a rat model

Aims

In the context of tendon degenerative disorders, the need for innovative conservative treatments that can improve the intrinsic healing potential of tendon tissue is progressively increasing. In this study, the role of pulsed electromagnetic fields (PEMFs) in improving the tendon healing process was evaluated in a rat model of collagenase-induced Achilles tendinopathy.

Methods

A total of 68 Sprague Dawley rats received a single injection of type I collagenase in Achilles tendons to induce the tendinopathy and then were daily exposed to PEMFs (1.5 mT and 75 Hz) for up to 14 days - starting 1, 7, or 15 days after the injection - to identify the best treatment option with respect to the phase of the disease. Then, 7 and 14 days of PEMF exposure were compared to identify the most effective protocol.

Results

The daily exposure to PEMFs generally provided an improvement in the fibre organization, a decrease in cell density, vascularity, and fat deposition, and a restoration of the physiological cell morphology compared to untreated tendons. These improvements were more evident when the tendons were exposed to PEMFs during the mid-acute phase of the pathology (7 days after induction) rather than during the early (1 day after induction) or the late acute phase (15 days after induction). Moreover, the exposure to PEMFs for 14 days during the mid-acute phase was more effective than for 7 days.

Conclusion

PEMFs exerted a positive role in the tendon healing process, thus representing a promising conservative treatment for tendinopathy, although further investigations regarding the clinical evaluation are needed.

Cite this article: Bone Joint Res 2020;9(9):613–622.

Effect of Low Intensity Magnetic Field Stimulation on Calcium-Mediated Cytotoxicity After Mild Spinal Cord Contusion Injury in Rats

BACKGROUND

Magnetic field (MF) stimulation has the potential to reduce secondary damage and promote functional recovery after neural tissue injury. The study aimed to observe the effect of very low intensity (17.96µT) MF on general body condition, secondary damage, pain status, and locomotion.

METHODS

We exposed rats to MF (2 h/day × 3 weeks) after 6.25 mm contusion spinal injury. Locomotor behavior was evaluated by BBB score, pain assessment was done by recording threshold for tail flick, expression of voltage-gated calcium channels and extent of secondary damage in the spinal cord was assessed by immunofluorescence and Cresyl violet staining, respectively.

RESULTS

A significant (p ≤ .001) improvement in bladder function as well as BBB score was observed after MF exposure in comparison with sham and SCI over the observation period of 3 weeks. SCI group showed an increase in the threshold for vocalization after discharge, which decreased following MF exposure. Cresyl violet staining showed significantly higher tissue sparing (73%) at the epicenter after MF exposure when compared to SCI group. This was accompanied with a significant decrease in calcium channel expression in MF group as compared to SCI.

CONCLUSION

The results suggest facilitation of sensory-motor recovery after MF exposure, which could be due to attenuation of secondary damage and calcium-mediated excitotoxicity in a mild contusion rat model of SCI.