Effect Of Magnetic Field Stimulation Research Articles

Dual Role of Low Frequency Magnetic Field on Neuroinflammation Induced Dendritic Trimming And Memory Impairment on Rat Model of Sporadic Alzheimer’s Disease

AbstractBackgroundGliosis and dendritic loss is reported to be secondary to the amyloid beta (Aß) and hyperphosphorylated tau (hp‐tau) production in Alzheimer’s disease(AD) brain. STZ administration is reported to induce sporadic AD. Previous clinical or preclinical studies on effect of rTMS treatment in AD patients or APP23 mice showed cognitive improvement alone or as adjuvant therapy along‐with amelioration of the glial aggravation in the hippocampus. However, studies on the effect of magnetic field stimulation on the gliosis related dendritic trimming in animal models of sporadic AD is elusive. Therefore, in the present study we have looked in to the effect of extremely low frequency magnetic field stimulation (ELF‐MF; 17.96µT, 50Hz, 2hr/day) for one month post‐injection of STZ (bilateral, 3mg/kg).MethodTotal 45 animals were (ethical no. 937/IAEC/2016) randomly divided into five groups: Control, Sham, AD, Sham+MF and AD+MF. After assessing retention of spatial and avoidance memory using Morris water maze and passive avoidance step down test on 30th day, animals were sacrificed and tissues processed for oxidative stress and immunofluorescence, Golgi‐Cox staining.ResultBehavioural analysis revealed spatial memory improvement with no effect on the avoidance memory loss in AD+MF group as compared to AD group. We also found significant decrease in superoxide dismutase, catalase, GSH and increase in malon‐di‐aldehyde (MDA) in AD group. ELF‐MF treatment only reduced MDA level in hippocampus and frontal cortex. GFAP, IBA‐1 and hp‐tau (ser356) positive cells were found to be reduced in AD+MF group, as compared to all groups except Control. Sholl analysis revealed partial improvement of reduction in the number of intersection, bifurcation and length in basal and apical dendrite in the AD group after ELF‐MF treatment in CA3 layer. Convex hull analysis revealed a contradictory result showing reduction in apical (p = 0.018) and increase in basal dendrite (p = 0.038) of AD group as compared to control.ConclusionThese findings suggests dual role of ELF‐MF exposure on STZ model of AD showing improvement of spatial memory by reducing the gliosis induced dendritic loss but loss in avoidance memory.

Dual role of low frequency magnetic field on neuroinflammation induced dendritic trimming and memory impairment on rat model of sporadic Alzheimer’s disease

Gliosis and dendritic loss is reported to be secondary to the amyloid beta (Aß) and hyperphosphorylated tau (hp‐tau) production in Alzheimer’s disease(AD) brain. STZ administration is reported to induce sporadic AD. Previous clinical or preclinical studies on effect of rTMS treatment in AD patients or APP23 mice showed cognitive improvement alone or as adjuvant therapy along‐with amelioration of the glial aggravation in the hippocampus. However, studies on the effect of magnetic field stimulation on the gliosis related dendritic trimming in animal models of sporadic AD is elusive. Therefore, in the present study we have looked in to the effect of extremely low frequency magnetic field stimulation (ELF‐MF; 17.96µT, 50Hz, 2hr/day) for one month post‐injection of STZ (bilateral, 3mg/kg). Total 45 animals were (ethical no. 937/IAEC/2016) randomly divided into five groups: Control, Sham, AD, Sham+MF and AD+MF. After assessing retention of spatial and avoidance memory using Morris water maze and passive avoidance step down test on 30th day, animals were sacrificed and tissues processed for oxidative stress and immunofluorescence, Golgi‐Cox staining. Behavioural analysis revealed spatial memory improvement with no effect on the avoidance memory loss in AD+MF group as compared to AD group. We also found significant decrease in superoxide dismutase, catalase, GSH and increase in malon‐di‐aldehyde (MDA) in AD group. ELF‐MF treatment only reduced MDA level in hippocampus and frontal cortex. GFAP, IBA‐1 and hp‐tau (ser356) positive cells were found to be reduced in AD+MF group, as compared to all groups except Control. Sholl analysis revealed partial improvement of reduction in the number of intersection, bifurcation and length in basal and apical dendrite in the AD group after ELF‐MF treatment in CA3 layer. These findings suggests dual role of ELF‐MF exposure on STZ model of AD showing improvement of spatial memory by reducing the gliosis induced dendritic loss. However, inability to manage oxidative stress due to STZ, which may lead to avoidance memory deficit even after exposure period of one month.

Magnetoresponsive nanozyme: magnetic stimulation on the nanozyme activity of iron oxide nanoparticles.

The iron oxide nanoparticles (IONPs) that combine the nanozyme activity and magnetothermal properties have attracted significant interest for various biomedical applications. However, the effect of magnetic stimulation in fine-tuning the nanozyme activities remains unclear. Here, we have constructed a series of IONPs with different magneto-thermal conversion abilities, and systematically study the effect of magnetic field stimulation on the peroxidase (POD) activity of IONPs. The results show that POD activity is effectively amplified via an in situ alternating magnetic field (AMF) stimulation with no solution temperature rise, and the degree of activity enhancement is closely related to the magnetic heating ability of the IONPs, confirming the origin of activity enhancement arises from the local magnetothermal effect. As the first report to prove magnetothermal regulation on nanozyme activity and to shed lights on the underlying correlation between activity enhancement and the intrinsic specific absorption rate (SAR), this work is expected to provide important support for future design of new magnetoresponsive nanozymes in various practical applications.

Cardiac tissue engineering in magnetically actuated scaffolds

Cardiac tissue engineering offers new possibilities for the functional and structural restoration of damaged or lost heart tissue by applying cardiac patches created in vitro. Engineering such functional cardiac patches is a complex mission, involving material design on the nano- and microscale as well as the application of biological cues and stimulation patterns to promote cell survival and organization into a functional cardiac tissue. Herein, we present a novel strategy for creating a functional cardiac patch by combining the use of a macroporous alginate scaffold impregnated with magnetically responsive nanoparticles (MNPs) and the application of external magnetic stimulation. Neonatal rat cardiac cells seeded within the magnetically responsive scaffolds and stimulated by an alternating magnetic field of 5 Hz developed into matured myocardial tissue characterized by anisotropically organized striated cardiac fibers, which preserved its features for longer times than non-stimulated constructs. A greater activation of AKT phosphorylation in cardiac cell constructs after applying a short-term (20 min) external magnetic field indicated the efficacy of magnetic stimulation to actuate at a distance and provided a possible mechanism for its action. Our results point to a synergistic effect of magnetic field stimulation together with nanoparticulate features of the scaffold surface as providing the regenerating environment for cardiac cells driving their organization into functionally mature tissue.

Effects of Magnetic Stimulation on Oxidative Stress and Skeletal Muscle Regeneration Induced by Mepivacaine in Rat

We investigated the effect of magnetic field stimulation (MS) on oxidative damage and skeletal muscle injury prompted by mepivacaine injection in the anterior tibial muscle of Wistar rats. The effects of mepivacaine and MS on oxidative stress were evaluated by lipid peroxidation, GSH levels and catalase activity. Muscle regeneration was analyzed by haematoxylin-eosin stained, NADH-TR histochemical reaction, desmin immunostaining as well as by morphometric parameters such as fibers density and fiber area were evaluated. Our data revealed that mepivacaine induced oxidative stress, that MS prevents the harmful effects induced by mepivacaine and that it facilitates the regeneration process of skeletal muscle. In conclusion, the results show the ability of MS to modify skeletal muscle response to mepivacaine.