右美托咪定通过抑制脊髓星形胶质细胞活化改善甲醛诱导的急性炎性痛

目的 探讨右美托咪定（DEX）在0.1%甲醛诱导的急性炎性痛中的作用。 方法 将30只ICR雌性小鼠随机分成生理盐水对照（NS）组、甲醛（F）组、右美托咪定+甲醛（DEX+F）组。向右后爪足底注射25 μl 0.4%甲醛建立小鼠急性炎性痛模型，在甲醛注射前1 h，DEX+F组小鼠腹腔注射DEX，NS组和F组小鼠腹腔注射等体积生理盐水。以小鼠舔咬足累计时间评价自发痛行为。采用免疫组织化学法和Western blotting检测脊髓星形胶质细胞标记物胶质纤维酸性蛋白（GFAP）的表达。 结果 自发痛评分结果显示，与NS组相比， F组小鼠出现典型的双相痛反应；与F组相比，DEX+F组小鼠的第Ⅰ时相痛（P<0.001）和第Ⅱ时相痛（P<0.001）累计时间明显减少。免疫组织化学结果显示，与NS组相比，F组小鼠脊髓后角GFAP阳性细胞数目明显增多（P<0.001）；与F组相比，DEX+F组小鼠脊髓后角GFAP阳性细胞数目明显减少（P<0.001）。Western blotting结果显示，与NS组相比， F组小鼠脊髓GFAP表达明显增加（P<0.05）；与F组相比，DEX+F组小鼠脊髓GFAP表达明显减少（P<0.05）。 结论 DEX可能是通过抑制小鼠脊髓星形胶质细胞的活化从而改善甲醛诱导的急性炎性痛。

Dexmedetomidine alleviates formaldehyde induced pain by inhibiting astrocytes activation in spinal cord

Objective To investigate the effect of dexmedetomidine（DEX）on formaldehyde-induced acute inflammatory pain. Methods Thirty female ICR mice were randomly divided into three groups, including normal saline control (NS) group, formaldehyde（F）group and dexmedetomidine + formaldehyde (DEX+F) group. 0.1% formaldehyde solution was injected into subcutaneous tissue of mice right hind paw to establish acute inflammatory pain model. An hour before formalin injection, mice were intraperitoneal injected with DEX in DEX+F group, and mice were intraperitoneal injected with equal volume saline in NS group and F group. The expression of spinal cord glial fibrillary acidic protein (GFAP）, which is a astrocytes marker, was detected by immunohistochemistry and Western blotting. Results Spontaneous pain score showed that compared with the NS group, the F group had typical biphasic pain response; while compared with the F group, the DEX+F group showed a significant decrease in the first (P<0.001) and second phase pain (P<0.001). Immunohistochemical result showed that compared with the NS group, the F group had an increase number of GFAP positive cells in the posterior horn of the spinal cord (P<0.001). However, the DEX+F group showed a decrease number of GFAP positive cells in the posterior horn of spinal cord compared with the F group (P<0.001). Western blotting result showed that compared with the NS group, the F group had increased expression of GFAP in the spinal cord (P<0.05). Compared with the F group, the DEX+F group showed decreased GFAP expression in the spinal cord (P<0.05). Conclusion DEX may improve formaldehyde-induced acute inflammatory pain in mice by inhibiting the activation of astrocytes in the spinal cord.