Chemokine CXCL10/CXCR3 signaling contributes to neuropathic pain in spinal cord and dorsal root ganglia after chronic constriction injury in rats.

Inflammatory cytokines and chemokines play essential roles in the occurrence and persistence of neuropathic pain (NP). Chronic constriction injury (CCI) enhances the activation of p-ERK, which is involved in neuropathic pain. Although the chemokine CXCL10 and its receptor CXCR3 are implicated in the pathophysiology of itch, it is largely unexplored for neuropathic pain. In this study, we determined the role of the CXCL10-CXCR3 axis in NP using a well-established CCI model. CCI significantly induced mechanical allodynia and thermal hyperalgesia. Following the pain course, a significant increase of CXCL10 and CXCR3 in both dorsal root ganglion (DRG) neurons and spinal cord (SC) neurons was detected in rats. Furthermore, intrathecal injection of CXCR3 inhibitor AMG487 was found to attenuate pain hypersensitivity in a dose-dependent manner in CCI. The expression of p-ERK was also depressed after intrathecal injection of AMG487 associated with a significant laxation of hyperalgesia, which demonstrated that the interaction of CXCL10/CXCR3 possibly took part in neuropathic pain by regulating p-ERK signaling in the SC. Overall, these findings demonstrate that the CXCL10/CXCR3 signaling pathway is critical in CCI.