Abstract: Objective To explore the effects of Jiaji electroacupuncture on the cortical somatosensory evoked potentials(CSEP) and promotion of the function recovery in rats with spinal cord injury(SCI).Methods The experiment was performed in the Medical Experimental Center of Heilongjiang University of Chinese Medicine from November 2008 to February 2009. ①Allen's injury model of T₁₀ spinal cord was established in SD rats with strike force of 50 g·cm. Fifty SD rats were divided into sham operated group (group A), only SCI group (group B), MP treatment group (group C), MP treatment+6 hours after SCI electroacupuncture treatment group (group D) and MP treatment+2 weeks after SCI electroacupuncture treatment group (group E) by means of random number table, ten rats in each group. For groups C, D and E first administration of MP (30 mg/kg) was taken within half hour after SCI, followed by 23 successive administration of MP(5.4 mg/kg·h) for every each hour. Equal amount of normal saline was given group B as that for group B. For groups D and E, electroacupuncture treatment was began 6 hours and 2 weeks after SCI respectively. ② Acupuncture method: The filiform needles of 0.25 mm×25 mm were vertically inserted into the acupoints 5 mm deeply, which were located at 4 mm away from the bilateralis of the lower margin of T₈ and T₁₂spinous process. KWD-808Ⅱ Electroacupuncture instrument was adopted with dilatational wave of AC PULSE current. The current intensity was 2 mA and the frequency was 2/100 Hz. Needles were kept in muscles for 30 minutes once a day, until the 8th week. ③Observation index: BBB score was used once a week at 1st, 2nd, 4th, 6th, 8th weeks and CSEP was observed once a week at 2nd, 4th, 6th, 8th weeks after SCI. Results 50 SD rats were all involved in the result analysis. The BBB score and the latency period of P1 in CSEP in each group were normal, there was no significant difference among them(P>0.05); The BBB score was less and the latency period was longer in SCI groups than that in group A, the difference was significant(P<0.05); At 1st week after SCI: The score was less than 7 in SCI groups (P>0.05); At 2nd week: the score in groups C, D and E was more than that in group B (P<0.05),but there was no significant difference among groups C, D and E (P>0.05); There was no significant difference among the latency period of SCI groups (P>0.05); From 4th to 8th weeks the score was the most and the latency period was the shortest in group D among SCI groups (P<0.05); At 4th week: The score was more and the latency period was shorter in groups E and C than that in group B (P<0.05), but there was no significant difference between groups C and E (P>0.05); At 6th week: The score was more and the latency period was shorter in group E than that in groups C and B (P<0.05), the score was the fewest and the latency period was longest in group B among SCI groups (P<0.05); At 8th week: The score was more and the latency period was shorter in group E than that in groups C and B (P<0.05), but there was no significant difference among group C and B (P>0.05).Conclusion The Jiaji electroacupuncture has promotion of the function recovery in rats with SCI and the effects of early electroacupuncture intervention are better than the later stage.

Key words: Jiaji electroacupuncture, rats with spinal cord injury, cortical somatosensory evoked potentials (CSEP), Basso-Beattie-Bresnahan score(BBB)