Effects of Continuous Repetitive Transcranial Magnetic Stimulation on Pain Response in Spinal Cord Injured Rat

ABSTRACT

OBJECTIVE: To investigate the effects of continuous repetitive transcranial magnetic stimulation (rTMS) on pain response in spinal cord injured rat. METHOD: Forty Sprague-Dawley rats (200~250 grams, female) were used. Thoracic spinal cord (T9) was contused using New York University (NYU) spinal cord impactor. Ten gram weight rod was dropped from a height of 25 mm to produce spinal cord contusion model with moderate injury. The animals were randomly assigned to two groups one exposed to real magnetic stimulation (real-rTMS group) and the other not exposed to magnetic stimulation (sham-rTMS group). rTMS was applied for 8 weeks. To assess the effect of continuous rTMS on below-level pain responses after spinal cord injury (SCI), the hindpaw withdrawal response for thermal stimuli, cold stimuli and mechanical stimuli were compared between two groups. RESULTS: Behavioral response for pain showed that hindpaw withdrawal response for cold stimuli was reduced significantly from 4 weeks after SCI in real-rTMS group compared with sham group (p<0.05). CONCLUSION: These results suggest that continuous rTMS may have beneficial effects on attenuation of cold allodynia after SCI, and it might be an additional non-invasive therapeutic method in patients with chronic neuropathic pain after SCI.