Effect of artemisinin on neuropathic pain mediated by P2X4 receptor in dorsal root ganglia

Neuropathic pain is a type of chronic pain caused by nervous system damage and dysfunction. The pathogenesis of chronic pain is complicated, and there are no effective therapies for neuropathic pain. Studies show that the P2X(4) receptor expressed in the satellite glial cells (SGCs) of dorsal root ganglia (DRG) is related to neuropathic pain. Artemisinin is a monomeric component extracted from traditional Chinese medicine and has a variety of important pharmacological effects and potential applications. This study observed the effect of artemisinin on neuropathic pain and delineated its possible mechanism. The chronic constriction injury (CCI) rat model was used in this study. The results demonstrated that artemisinin relieved pain behaviors in the CCI rats, inhibited the expression of P2X(4) receptor in the DRG, and decreased the ATP-activated currents in HEK293 cells transfected with P2X(4) plasmid. Dual-labeling immunofluorescence showed that the coexpression of P2X(4) receptor and glial fibrillary acidic protein (GFAP) in the DRG of CCI rats was increased compared to control rats. After CCI rats were treated with artemisinin, the coexpression of P2X(4) receptor and GFAP in the DRG was significantly decreased compared to the CCI group. This finding suggested that artemisinin could inhibit the nociceptive transmission mediated by P2X(4) receptor in the DRG SGCs and thus relieve pain behaviors in the CCI rats. (C) 2017 Elsevier Ltd. All rights reserved.