Effects of P2X4 receptor in spinal microglia on rrTNF-induced pathologi-cal pain / 中国病理生理杂志

ABSTRACT

AIM:To investigate the effects of P2X4 receptor on peri-sciatic administration of recombinant rat TNF-α(rrTNF)-induced mechanical allodynia.METHODS:Male Sprague-Dawley rats (180~200 g) were used in the experiments.The levels of P2X4 receptor on day 3, day 7 and day 14 after peri-sciatic administration of rrTNF were exam-ined by Western blot, and the location of P2X4 receptor in the spinal dorsal horn was observed by double immunofluores-cence staining.The changes of 50%paw-withdrawal thresholds of the rat were detected by behavioral test, and the level of TNF-αin the spinal dorsal horn was also examined by Western blot when TNP-ATP was intrathecally injected before the ad-ministration of rrTNF.RESULTS:Compared with control group, the expression of P2X4 receptor in the spinal dorsal horn on the ipsilateral side significantly increased on day 3, day 7 and day 14 (P<0.01) after rrTNF (100 ng/L) administra-tion.P2X4 receptor was co-localized only with microglia, but not with neurons or astrocytes.Intrathecal injection of TNP-ATP before rrTNF administration prevented mechanical allodynia induced by rrTNF and inhibited the upregulation of TNF-αin the spinal dorsal horn.CONCLUSION:P2X4 receptors in microglia may be involved in rrTNF-induced mechanical allodynia by the upregulation of TNF-αin the spinal dorsal horn.