rTMS Regulates the Balance Between Proliferation and Apoptosis of Spinal Cord Derived Neural Stem/Progenitor Cells

Abstract

Repetitive transcranial magnetic stimulation (rTMS) is a noninvasive technique that uses electromagnetic fields to stimulate the brain. rTMS can restore an impaired central nervous system and promote proliferation of neural stem/progenitor cells (NSPCs), but optimal stimulus parameters and mechanisms underlying these effects remain elusive. The purpose of this study is to investigate the effect of different rTMS stimulus parameters on proliferation and apoptosis of spinal cord-derived NSPCs, the expression of brain-derived neurotrophic factor (BDNF) after rTMS, and the potentially underlying pathways. NSPCs were isolated from mice spinal cord and stimulated by different frequencies (1/10/20 Hz), intensities (0.87/1.24/1.58 T), and number of pulses (400/800/1,500/3,000) once a day for five consecutive days. NSPC proliferation was analyzed by measuring the neurosphere diameter and Brdu staining, apoptosis was detected by cell death enzyme-linked immunosorbent assay (ELISA) and flow cytometry, and NSPC viability was assessed by cell counting kit-8 assay. We found that specific parameters of frequency (1/10/20 Hz), intensity (1.24/1.58 T), and number of pulses (800/1,500/3,000) promote proliferation and apoptosis (p < 0.05 for all), but 20 Hz, 1.58 T, and 1,500 pulses achieved the optimal response for the NSPC viability. In addition, rTMS significantly promoted the expression of BDNF at the mRNA and protein level, while also increasing Akt phosphorylation (Thr308 and Ser473; p < 0.05). Overall, we identified the most appropriate rTMS parameters for further studies on NSPCs in vitro and in vivo. Furthermore, the effect of magnetic stimulation on NSPC proliferation might be correlated to BDNF/Akt signaling pathway.

LINGO-1 regulates Wnt5a signaling during neural stem and progenitor cell differentiation by modulating miR-15b-3p levels

“…For induction of cell differentiation, we followed the Gibco Neurobiology Protocol Handbook, as previously described [ 10 ]. sp-NSPCs were allowed to adhere to cover slips coated with poly- l -lysine (0.01%, P4707, Sigma) and laminin (10 μg/mL, L2020, Sigma) in NSPC growth medium for 1 day.…”

Repetitive Transcranial Magnetic Stimulation Improves Neurological Function and Promotes the Anti-inflammatory Polarization of Microglia in Ischemic Rats

“…For such purposes, many studies focus on the mechanism of rTMS acting on the neural stem cells (NSCs) and neural precursor cells (NPCs), which are related to neurogenesis, and astrocytes or microglia connected with neuroinflammation ( Hong et al, 2020 ). For instance, rTMS has therapeutic effects on depression because it can reverse the decrease of NSCs and enhance neurogenesis, and rTMS could regulate the balance between proliferation and apoptosis of NSCs ( Zhao et al, 2019 ). For neuroprotective effect, it has been reported that rTMS could improve functional recovery by inhibiting neurotoxic polarization of astrocytes in ischemic rats, which means rTMS may regulate inflammation through the action of neural glial cells ( Sasso et al, 2016 ; Cullen et al, 2019 ; Clarke et al, 2021 ).…”