Exposure to ELF- magnetic field promotes restoration of sensori-motor functions in adult rats with hemisection of thoracic spinal cord

Abstract

Clinically effective modalities of treatment for spinal cord injury (SCI) still remain unsatisfactory and are largely invasive in nature. There are reports of accelerated regeneration in injured peripheral nerves by extremely low-frequency pulsed electromagnetic field (ELF-EMF) in the rat. In the present study, the effect of (50 Hz), low-intensity (17.96 μT) magnetic field (MF) exposure of rats after-hemisection of T13 spinal cord (hSCI) was investigated on sensori-motor and locomotor functions. Rats were divided into hSCI (sham-exposed) and hSCI+MF (MF: 2 h/d X 6 weeks) groups. Besides their general conditions, locomotor function by Basso, Beattie, and Brenahan (BBB) score; motor responses to noxious stimuli by threshold of tail flick (TTF), simple vocalization (TSV), tail flick latency (TFL), and neuronal excitability by H-reflex were noted. It is found that, in the hSCI+MF group, a statistically significant improvement over the hSCI control group was noted in BBB score from post-SCI wk2 and TFL and TTF by post-hSCI wk1 and wk3, respectively. Correspondingly, TSV gradually restored by post-hSCI wk5.The threshold of H-reflex was reduced on ipsilateral side vs. contralateral side in hSCI and hSCI+MF group. A complete bladder control was dramatically restored on post-hSCI day4 (vs. day7 of hSCI group) and the survival rate was 100% in the hSCI+MF group (vs. 90% of hSCI group). The results of our study suggest that extremely low-frequency (50 Hz), low-intensity (17.96 μT) MF exposure for 2 h/d x 6wks promotes recovery of sensori-motor behavior including locomotion and bladder control both in terms of temporal pattern and magnitude in hemisection injury of (T13) spinal cord rats.

Iron oxide nanoparticles and magnetic field exposure promote functional recovery by attenuating free radical-induced damage in rats with spinal cord transection

“…Achievement of complete spontaneous voiding of the bladder also improved on treatment (F [3,35] = 44.38, P = 0.0001). Post hoc analysis revealed that the most rapid recovery occurred in the NP + MF group (P , 0.001), although the MF and NP groups also recovered earlier than the SCI group (P , 0.001, Figure 3D).…”

“…[26][27][28][29][30][31] In rat models of spinal cord injury (SCI), exposure to a low intensity MF results in significant improvement in locomotor, sensorimotor, and autonomic function. [32][33][34][35][36] Stimulation of the motor cortex by repetitive transcranial magnetic stimulation is beneficial, especially in lower thoracic SCI lesions, because it activates the central pattern generator via descending serotonin pathways. 28 In vitro, exposure to an MF increases the overall viability of mouse monoclonal hippocampal HT22 cells and has a neuroprotective effect against oxidative stressors.…”

“…These results are comparable with previous reports of repeated low-intensity MF stimulation in SCI rats and may be mediated by the effects of the MF on free radical-induced secondary injury or by activation of the central pattern generator center for locomotion by serotonin pathways. [28][29][30][31][32][33][34][35][36] 5-Hydroxytryptamine has an important role in modulating the excitability of motor and sensory neurons in the spinal cord, thereby influencing locomotion and sensorimotor behavior. [51][52][53][54][55] Exposure to an MF has been shown to restore the metabolism, synthesis, and distribution of 5-hydroxytryptamine in the spinal cord and brain.…”

Extremely Low Frequency Magnetic Field Exposure Attenuates Pain By Inactivation Of Descending Facilitatory System In Complete Spinal Cord Injured Rats

“…[6,11,12] More over, ELF-MF in rats has been reported from our laboratory to improve the quality of life after SCI by significantly improving locomotor recovery, autonomic control of urinary bladder, sensorimotor function, osteoporosis and eating behavior. [5,11,13,14] Recently, we have reported the facilitation of neuroregenerative processes also by it after SCI. [14] However, we are still ignorant about the influence of ELF-MF on pain modulation status after SCI.…”

“…[1][2][3][4] Previous studies from our laboratory have also reported hyperalgesia to phasic whereas, hypoalgesia to tonic pain stimuli in both hemi and complete transection models of SCI rats. [5,6] The underlying mechanism for post-SCI pain is believed to be hyper responsiveness of neurons; increase in blood flow; increase in spontaneous activity; presence of abnormal burst activity of spinal and supraspinal neurons in brain stem, limbic areas, arcuate, hypothalamus, anterior cingulate cortex besides alteration in neurotransmitter/ modulator profile favouring hyperalgesia. [3,[7][8][9] These brain areas exert their influence on the perception, processing and response to noxious stimuli via descending modulatory system that include independent facilitatory and inhibitory systems.…”