Prolonged Repetitive Trans-Spinal Magnetic Stimulation Promotes Superior Functional Recovery After Severe Spinal Cord Injury in Rats

Spinal cord injury (SCI) results in permanent disability in affected individuals. Immediately after SCI, a cascade of cellular and molecular events leads to the formation of a spinal scar. To date, no curative treatment is available for paraplegic or tetraplegic patients, underscoring the urgent need for pre-clinical research into innovative therapeutic strategies. Our laboratory has recently demonstrated that the spinal scar can be noninvasively modulated using repetitive trans-spinal magnetic stimulation (rTSMS). In both rat and mouse models, we showed that rTSMS applied for 14 consecutive days starting the day after injury modulates the lesion environment and promotes functional recovery. However, in rats with severe SCI, the effects on locomotion remain moderate. In this study, to move closer to potential clinical translation, we investigated whether extending rTSMS to 28 consecutive days could enhance recovery in a rat model of complete spinal cord transection. Based on detailed behavioral assessments, our results confirm that rTSMS improves locomotor recovery following severe SCI. These functional improvements are supported by immunohistochemical analyses of the lesion site. Notably, the beneficial effects of rTSMS appear to be maximized with 28 days of stimulation, with no observable adverse effects. This study provides further evidence that long-term rTSMS is a promising and safe approach, bringing us a step closer to its future clinical application in humans.