Abstract: Objective To investigate the differentially expressed miRNAs in the spinal dorsal horns of rats with chronic neuropathic pain, and predict the target genes of the miRNAs. Methods CCI(Chronic Constrictive Injury) rat model was established，and spinal dorsal horns were harvested when a peak pain was achieved on the 7th day post-op. Microarray analysis was applied to investigate the differentially expressed miRNAs in CCI rats, and the screened miRNAs were confirmed by real time RT-PCR. Furthermore, the possible target genes were predicted by three databases. Results miRNA microarray analysis showed the expression of miR-99b as significantly up-regulated, while the expressions of miR-674-3p，miR-879 and miR-325-5p as significantly down-regulated in the spinal dorsal horns of CCI rats compared with those in the sham and na?ve rats. The different expression profiles of the 4 miRNAs were confirmed by quantitative RT-PCR. About 26 target genes were predicted through the 3 databases based on the previous screened miRNAs. Conclusions Chronic neuropathic pain affecedt the expression of miRNAs. These miRNAs and target genes provided new clues for further research.

Key words: chronic pain, miRNA, microarray, real time PCR, spinal dorsal horn