Identification of the key genes associated with neuropathic pain.

Neuropathic pain is a chronic pain state associated with multiple etiologies that results in considerable social and economic burden. The identification of key genes associated with neuropathic pain is important for the development of novel therapies. Therefore, the present study downloaded the gene expression profile GSE15041 from the Gene Expression Omnibus database. The unverified gene chip was removed and the microarray data was normalized following quality control. The limma package in R was used to screen the differentially expressed genes (DEGs), followed by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis. Furthermore, a protein‑protein interaction (PPI) network based on the identified DEGs was constructed to select hub proteins, and reverse transcription‑quantitative polymerase chain reaction was performed to detect the expression of these proteins in a mouse model of neuropathic pain. In total, 86 common DEGs were identified. DEGs were significantly enriched in ̔extracellular space̓ and KEGG pathway enrichment analysis demonstrated that the DEGs were significantly enriched in inflammatory diseases and the mitogen‑activated protein kinase signaling pathway. The PPI network consisted of 27 nodes (proteins) and 47 PPI edges (interactions). Interleukin (IL)‑6, transcription factor AP‑1 (c‑Jun) and urikinase‑type plasminogen activator (Plau) were identified as hub proteins and key genes in neuropathic pain. The mRNA expression of these hub proteins was significantly increased in the neuropathic pain model, compared with the sham group. IL‑6, c‑Jun, and Plau may be involved in development of neuropathic pain and further research investigating the exact role of these key genes is required.