中文摘要：

目的 观察脊髓鞘内注射P2X7受体激动剂[3′-O-（4-Benzoyl）benzoyl ATP，BzATP]及抑制剂（brilliant blue G，BBG）对大鼠痛行为及脊髓背角小胶质细胞活化的影响。 方法 大鼠脊髓蛛网膜下腔内置管，制备给药模型后大鼠分为：对照组（给予磷酸盐缓冲液PBS）、BzATP组（给予P2X7受体激动剂）、BBG＋BzATP组（给予P2X7受体抑制剂＋激动剂）和BBG组（给予P2X7受体抑制剂），分别于给药0、1、3、5、7、11、14 d通过热辐射刺激法测定大鼠热痛阈，使用von Frey纤维丝测定大鼠机械痛阈，应用免疫组织化学技术观察不同时间点脊髓腰段（L4～L6）背角OX42表达的变化，并进行分析。 结果 大鼠鞘内给予BzATP后，大鼠表现出缩足和舔足等痛觉相关行为。行为学检测结果显示，大鼠鞘内给予P2X7受体激动剂后，动物热痛阈和机械痛阈下降，于给药第7天达最低（P〈0.01），停药后逐渐恢复至正常水平；若先给予P2X7受体抑制剂后再给予激动剂，则大鼠的热痛阈和机械痛阈无明显变化。免疫荧光双标检测结果显示，脊髓背角OX42阳性小胶质细胞表达P2X7受体。免疫组化检测结果显示大鼠脊髓背角OX42免疫反应在给予BzATP 7 d后明显增强（P〈0.01），停止给药后恢复至正常。 结论 脊髓背角小胶质细胞P2X7受体激活参与了神经病理性疼痛的发生与维持。

英文摘要：

Objective To determine the effects of intrathecal injection of P2X7 receptor agonist, 3′-O-（4-Benzoyl）benzoyl ATP （BzATP） and antagonist, Brilliant Blue G （BBG） on the activation of spinal dorsal horn microglia and pain related behaviors. Methods Totally 48 SD rats with intrathecal catheterization were randomly divided into 4 groups, control, BzATP group, BBG＋BzATP group and BBG group （n=12）. The rats of above groups received an intrathecal administration of phosphorylate buffer solution （PBS）, BzATP, BBG＋BzATP, and BBG, respectively since 3 d after catheterization for 7 continuous days. Pain threshold was assessed by thermal radiation and von Frey filament in 0, 1, 3, 5, 7, 11, and 14 d after administration. Expression of OX42 and P2X7 receptor in spinal dorsal horn of L4 to L6 was measured by immunofluoresence staining. Results After administration of BzATP, thermal hyperalgesia and mechanical allodynia appeared in the rats. The thermal withdrawl latency （TWL） and 50% paw withdrawl threshold （PWT） were decreased obviously from 1 d after injection and descended to the lowest at 7 d （P〈0.01）, then returned to the level of normal control slowly. And these results were reversed by the treatment of P2X7 receptor antagonist, BBG. The double labeled immunofluorescence results showed that the OX42 positive microglia expressed P2X7 receptor. Immunohistological assay showed that the reaction of OX42 was obviously increased after injection of 7 days’ treatment of BzATP （P〈0.01）, and then declined to the baseline after the end of administration. Conclusion Activation of spinal dorsal horn microglial P2X7 receptor plays essential roles in the incidence and progress of neuropathic pain.