Analgesic Effects of Transcranial Direct Current Stimulation on Central Neuropathic Pain in Spinal Cord Contusive Rat Model

The aim is to investigate the analgesic effect of transcranial direct current stimulation(tDCS) on central neuropathic pain(CNP) in spinal cord contusive rat model. Twenty Sprague-Dawley rats($250{\pm}50$ g, male) were used. Thoracic spinal cord(T10) was contused using New York University(NYU) spinal cord impactor. The animals were randomly assigned to two groups; GroupI: Non-treatment after SCI induction(n=10), GroupII: application of tDCS(0.1 mA, 20 min/time, 2 times/day, 5 days/6week) after SCI induction(n=10). Assess the effect of tDCS using the Basso Beattie Bresnahan(BBB) locomotor rating scales, Touch $test^{TM}$ sensory evaluator(TTSE), Plantar test$^{\circledR}$after contusion at the $2^{nd}$, $3^{rd}$, $4^{th}$, $5^{th}$, $6^{th}$ week and the immunohistochemistric response of c-fos in the thalamus, cerebral cortex after contusion at the $3^{rd}$, $6^{th}$ week after SCI. The scores of BBB scales were significantly different from $3^{rd}$week. TTSE were different significantly over time, but there were no differences at each evaluation times on between-measure time effects. Plantar test were different significantly over time and there were difference at the $4^{th}$, $6^{th}$ week after SCI on between-measure time effects. Also, immunohistochemistric response of c-fos was reduced significantly from $3^{rd}$, $6^{th}$ week after SCI in tDCS group compared with control group in thalamus and cortex. These results identified that tDCS of non-invasive therapeutic method may have beneficial analgesic effect on CNP after SCI with behavioral test and immunohistochemical test.