Transcranial magnetic stimulation through attenuating blood-spinal cord barrier disruption and reducing inflammatory
Qingqin Xu1, Zhongfu Zhang2, Yuqing Zhai2
1College of Rehabilitation Science, Shanghai University of Traditional Chinese Medicine, Shanghai 200000, China; Engineering Research Center for Traditional Chinese Medicine Intelligent Rehabilitation, Ministry of Education, Shanghai 200000, China; Department of Rehabilitation Medicine, The First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022, China.
Background:
Previous therapies for spinal cord injury (SCI) typically focus on the lesion site, neglecting the interconnected brain areas. Transcranial magnetic stimulation (TMS) is an emerging non-invasive neuromodulation technique, demonstrating potential in modulating the primary motor cortex to enhance SCI recovery.
Methods:
The modified Allen's method was used to establish an SCI rat model. High-frequency repetitive TMS (HF-rTMS) intervention was initiated on the second day after modeling and continued for 56 days. Bioinformatics analysis identified key genes involved in the SCI pathological process, including MMP9, IL-1β, and IL-18. This study explored the functions and mechanisms of these genes in HF-rTMS-mediated motor recovery in SCI rats.
Results:
Western blotting reveals that HF-rTMS decreases active-MMP9/pro-MMP9, TNF-α, IL-1β, and IL-18 proteins' expression, while increases β-DG, Occludin, Claudin-5, and ZO-1 proteins' expression in injured spinal cord (P < 0.001). Immunofluorescence staining further shows that HF-rTMS reduces MMP9 positive cells, while enhances Occludin, Claudin-5, and ZO-1 positive cells (P < 0.001). Evans Blue staining indicates that HF-rTMS reduces blood-spinal cord barrier (BSCB) permeability following injury, while ELISA results demonstrate that HF-rTMS attenuates serum levels of pro-inflammatory cytokines. Motor-evoked potentials (MEP) assessment, HE staining, and BBB score show that HF-rTMS shortens MEP latency, enhances MEP amplitude, reduces spinal cord damage and improves motor function (P < 0.001).
Conclusion:
These findings reveal that HF-rTMS may be associated with suppressing MMP9 activation, protecting tight junction proteins, diminishing basement membrane destruction, and maintaining BSCB integrity. Simultaneously, it may alleviate pro-inflammatory cytokine-induced inflammation, thereby reducing spinal cord tissue damage and promoting motor recovery after SCI.
