Mechanism of GABA Receptors Involved in Spasticity Inhibition Induced by Transcranial Magnetic Stimulation Following Spinal Cord Injury

The effect of high-frequency repetitive transcranial magnetic stimulation（r TMS） on spasticity following spinal cord injury（SCI） and the action mechanism were investigated. SCI models were established in Sprague-Dawley rats. Five groups were set up： normal control group, SCI-7 day（7D） model group, SCI-14 D model group, SCI-7D r TMS group and SCI-14 D r TMS group（n=10 each）. The rats in SCI r TMS groups were treated with 10 Hz r TMS at 8th day and 15 th day after SCI respectively. Motor recovery and spasticity alleviation were evaluated by BBB scale once a week till the end of treatment. Finally, different parts of tissues were dissected out for detection of GABA receptors using Western blotting and polymerase chain reaction（PCR） technique. The results showed that the BBB scores after treatment were significantly higher in SCI-7D r TMS group than in SCI-14 D r TMS group（P〈0.05）. The GABA receptors were down-regulated more significantly in SCI-14 D model group than in SCI-7D model group（P〈0.05）. At different time points, r TMS treatment could affect the up-regulation of GABA receptors： The up-regulation of GABA receptors was more obvious in SCI-7D r TMS group than in SCI-14 D r TMS treatment group（P〈0.05）. It was concluded that 10-Hz r TMS could alleviate spasticity following SCI and promote the motor recovery in rats, which might be attributed to the up-regulation of GABA receptors. It was also suggested that early high-frequency r TMS treatment after SCI may achieve more satisfactory curative effectiveness.