OBJECTIVETo explore the effects of low-and high-frequency electroacupuncture (EA) on the gene expression profiles in rat spinal dorsal horn (DH) under the physiological state, thus providing the information to find out the differences of different EA frequencies induced effects.

METHODSUsing cDNA microarray, the changes of the gene expressions in the DH were detected and compared between 2 Hz EA and 100 Hz EA at bilateral Zusanli (ST36) and Sanyinjiao (SP6). The differentially expressed genes were identified. The EASE scores were used to comprehensively analyze the gene functions (by Gene Ontology) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways.

RESULTS(1) After EA stimulation 1 150 genes/expressed sequence tags (ESTs) were differentially expressed by 2 Hz EA, while 1 270 genes/ESTs were differentially expressed by 100 Hz EA. (2) Both 2 Hz and 100 Hz EA could induce the modulation of the same 516 genes/ESTs in the same direction, which was correlated with neural signal transmission. (3) The differentially expressed genes regulated specifically by 2 Hz were correlated with neural plasticity. (4) The differentially expressed genes regulated specifically by 100 Hz were correlated with stress and immunoregulation.

CONCLUSIONSEither low-or high-frequency EA could extensively regulate the spinal cord information processing. The low-frequency EA participated more in the regulation of neural plasticity, while high-frequency EA had more significant effects on stress and immunoregulation.