Nerve root magnetic stimulation regulates the synaptic plasticity of injured spinal cord by ascending sensory pathway

JOURNAL/nrgr/04.03/01300535-202512000-00026/figure1/v/2025-01-31T122243Z/r/image-tiff Promoting synaptic plasticity and inducing functional reorganization of residual nerve fibers hold clinical significance for restoring motor function following spinal cord injury. Neuromagnetic stimulation targeting the nerve roots has been shown to improve motor function by enhancing nerve conduction in the injured spinal cord and restoring the synaptic ultrastructure of both the sensory and motor cortex. However, our understanding of the neurophysiological mechanisms by which nerve root magnetic stimulation facilitates motor function recovery in the spinal cord is limited, and its role in neuroplasticity remains unclear. In this study, we established a model of spinal cord injury in adult male Sprague-Dawley rats by applying moderate compression at the T10 vertebra. We then performed magnetic stimulation on the L5 nerve root for 3 weeks, beginning on day 3 post-injury. At day 22 post-injury, we observed that nerve root magnetic stimulation downregulated the level of interleukin-6 in the injured spinal cord tissue of rats. Additionally, this treatment reduced neuronal damage and glial scar formation, and increased the number of neurons in the injured spinal cord. Furthermore, nerve root magnetic stimulation decreased the levels of acetylcholine, norepinephrine, and dopamine, and increased the expression of synaptic plasticity-related mRNA and proteins PSD95, GAP43, and Synapsin II. Taken together, these results showed that nerve root magnetic stimulation alleviated neuronal damage in the injured spinal cord, regulated synaptic plasticity, and suppressed inflammatory responses. These findings provide laboratory evidence for the clinical application of nerve root magnetic stimulation in the treatment of spinal cord injury.