Effect of puerarin on P2X3 receptor involved in hyperalgesia after burn injury in the rat

The study investigated the effects of puerarin on P2X3 receptor involved in hyperalgesia after burn injury in the rat. Superficial second degree burn injury models were adopted. Mechanical withdrawal threshold (MWT) and thermal withdrawal latency (TWL) were measured and the P2X3 receptor expressions in dorsal root ganglion (DRG) from burn injury models rats were detected by immunohistochemistry, in situ hybridization, RT-PCR and western blot. MWL and TWL in untreated superficial second paw burn rats were reduced. MWL and TWL of puerarin-treated superficial second paw burn rats showed significant increase compared with untreated superficial second paw burn rats. Puerarin can decrease the hyperalgesia after burn injury. At day 3 post-burn, the expressions of P2X3 protein and mRNA in DRG neurons in untreated superficial second degree back burn group were increased significantly compared with sham back burn group, puerarin-treated back unburned control group, blank back control group, while in puerarin-treated superficial second degree back burn group, the P2X3 protein and mRNA expressions were decreased markedly. There is no significant difference in sham back burn group, puerarin-treated back unburned control group, blank back control group. Therefore, puerarin may reduce the nociceptive transmission of burn injury pain mediated by P2X3 receptor and alleviate P2X3 receptor involved in hyperalgesia after burn injury in the rats.