中文摘要：

目的：探讨腹腔注射右美托咪啶（dexmedetomidine,DEX）对糖尿病神经病理性疼痛（diabetic neuropathic pain,DNP）大鼠的镇痛作用以及对脊髓背角P2X3受体表达的影响.方法：建立DNP大鼠模型,检测大鼠机械痛阈;给予腹腔注射DEX（12.5、25、50 μg/kg.d）后,观察DEX对DNP大鼠的镇痛作用;免疫组化法检测大鼠L4～6脊髓背角P2X3受体表达变化.结果：糖尿病大鼠建模成功后28 d,糖尿病大鼠与正常大鼠比较机械痛阈值明显下降;从建模后35 d开始,DNP大鼠连续7d给予腹腔注射DEX后其机械痛阈值显著升高,脊髓背角P2X3受体表达显著下调;机械痛阈值升高幅度以及脊髓背角P2X3受体表达下调幅度与DEX剂量相关.结论：腹腔注射DEX通过下调DNP大鼠脊髓背角P2X3受体表达,对DNP大鼠产生镇痛作用.

英文摘要：

Objective： To investigate the analgesic role of dexmedetomidine （DEX） on neuropathic pain in streptozotocin-induced diabetic rats and the alterations of spinal dorsal horn （SDH） P2X3 receptor expression. Methods： Male Sprague-Dawley （SD） rats were used in this study. Diabetes was induced by peritoneal injection with streptozotocin（STZ, 80 mg/kg） and the pain threshold was characterized by the mechanical withdrawal threshold testing. DEX （ 12.5, 25, 50 μg/kg.d ） was administered on 35 d post STZ injection for 7 consecutive days; The expressions of P2X3 receptor in L4-6 SDH were detected by immunohistochemisty assay. Results： The diabetic neuropathic pain （DNP） rats showed a significant decrease on MWT values accompanied with P2X3 receptor expressions increased in L4-6 SDH on 28d after STZ, i.p; The DNP rats were administered with DEX intraperitoneally for 7 consecutive days dose-dependently increased the MWT values and down-regulated P2X3 receptor expression in L4-6 SDH. Conclusions： These results imply that DEX exerts an analgesic effect in DNP rats via down-regulation of L4-6 SDH P2X3 receptor expression.