目的：研究P2X4受体在坐骨神经周围给予重组大鼠TNF-α（ recombinant rat TNF-α， rrTNF）引起的机械痛敏中的作用。方法：采用雄性SD大鼠（180～200 g），Western blot检测坐骨神经周围给予rrTNF后3 d、7 d和14 d脊髓背角P2X4受体的表达水平，免疫荧光双染观察脊髓背角P2X4受体的表达部位；在坐骨神经周围给予rrTNF的大鼠前鞘内注射TNP-ATP，行为学检测大鼠50％机械撤足阈值的变化，Western blot检测脊髓背角TNF-α的表达是否发生变化。结果：与对照组相比，坐骨神经周围给予rrTNF（100 ng／L）后3 d、7 d和14 d同侧脊髓背角P2X4受体的表达水平明显升高（ P＜0.01）；P2X4受体只表达于小胶质细胞中，神经元和星形胶质细胞中没有表达。坐骨神经周围给予rrTNF的大鼠前鞘内注射TNP-ATP可防止rrTNF诱导的机械痛敏并抑制脊髓背角TNF-α的上调。结论：小胶质细胞P2X4受体可能通过上调脊髓背角的TNF-α介导rrTNF诱导的机械痛敏。%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.
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