ABSTRACT
Objective:To explore the effect of combining repetitive transcranial magnetic stimulation (rTMS) with treadmill training in treating spinal cord injury (SCI).Methods:Fifty female Sprague-Dawley rats were randomly divided into a sham-operation (C) group, an SCI group, a treadmill training (TT) group, a treadmill training followed by rTMS (TR) group and an rTMS followed by treadmill training (RT) group. The C group only underwent laminectomy without spinal cord injury, while the model of T9 incomplete spinal cord injury was established in the other groups using the Louisville Injury System Apparatus impactor. One week after the operation the TT began. The TR group received rTMS immediately after the treadmill training and the RT group received it before. The treadmill′s speed started at 3.6m/min and gradually increased to 6m/min within 1 week. There was one 15min session a day, 5 days a week, for 8 weeks in total. The rTMS intensity was 30% of the maximum output intensity at 10Hz in 5s bursts with an interval of 25s. It lasted 10min, for a total of 1000 pulses. Hind limb motor functioning was evaluated using the Basso, Beattie & Bresnahan (BBB) locomotor rating scale and a grid walking test. The H max/M max ratio was used to quantify the excitability of the motor neurons. Immunohistochemistry was employed to detect the expression of 5-hydroxytryptamine (5-HT), 5-hydroxytryptamine 1A receptor (5-HT 1AR) and 5-hydroxytryptamine 2A receptor (5-HT 2AR). Results:The average BBB scores of the RT group were significantly higher than the SCI group′s averages from the 7th to 9th week after the injury. At the ninth week the average BBB score of the RT group was significantly higher than the TT group′s average. At the eighth and ninth week the average BBB scores of the TR group were significantly higher than in the SCI group. The number of drops in the RT group was significantly lower than in the SCI group at the seventh and ninth week. At the ninth week, the number of drops of the TR group was significantly lower compared with the SCI group. The H max/M max ratio of the SCI group was significantly higher than in the C and TR groups at the fifth and ninth week, while that of the TR group was significantly lower than the SCI group′s ratio at the ninth week. The expression of 5-HT, 5-HT 1AR and 5-HT 2AR in the RT and TR groups was significantly higher than in the SCI group, and the relative 5-HT 1AR density of the RT and TR groups was significantly higher than in the SCI and TT groups. Compared with the other 4 groups, the expression of 5-HT 2AR in the SCI group had increased significantly. Conclusions:Combining rTMS with treadmill training can significantly promote the recovery of locomotor function after incomplete spinal cord injury.