Abstract: Objective To investigate the effect of repetitive transcranial magnetic stimulation(rTMS)on the spinal segmental excitability after spinal cord injury in adult rats.MethodsT 10 spinal cord injury models were made with weight-drop method.8 weeks later,rTMS were applied to the experimental group at 0.5 Hz suprathreshold stimulation,500 pulses daily for 4 weeks.Spinal cord injury rats without stimulation and normal rats were used as controls.At different time points,electronic evoked F-wave were measured.The ratio of F-wave amplitude to M-wave amplitude(F/M)were compared among these groups.Immunohistochemistry was used to detect the expression of 5-hydroxytryptamine(5-HT)in the rostral and caudal lesion segments.ResultsThe ratio of F/M increased significantly(P<0.01)8 weeks after spinal cord injury compared with baseline ratio and regressed significantly(P<0.01)after 4 weeks of rTMS.Expression of 5-HT in grey matter around lesion was decreased after spinal cord injury and increased significantly(P<0.01)both in the rostral and caudal lesion segments in rTMS treatment group.ConclusionThe increased spinal segmental excitability after spinal cord injury can be regressed by rTMS,which may be resulted in increased expression of 5-HT.

Key words: repetitive transcranial magnetic stimulation (rTMS), spinal cord injury (SCI), 5-hydroxytryptamine (5-HT), F-wave