福尔马林致痛后小鼠不同脑区内FOS蛋白的表达

FOS expression in supraspinal regions after formalin-induced pain in mice

目的 探讨小鼠足底注射福尔马林致痛后不同脑区内FOS蛋白的表达情况。方法 将5%福尔马林溶液注射到小鼠后肢足底皮下，观察注射后60min内小鼠的自发痛反应；用免疫组织化学染色技术观察注射后2h同侧脊髓背角及不同脑区内FOS蛋白阳性神经元的分布情况和数量。结果 行为学结果显示：注射福尔马林60min后小鼠的舔/咬足时间及缩足次数呈现典型的双相变化。免疫组织化学检测结果显示：注射福尔马林2h后同侧脊髓背角、下丘脑室旁核、丘脑中间背侧核、前扣带回皮质、岛叶皮质及杏仁核内FOS阳性神经元的数量明显增加，同时海马齿状回区FOS蛋白的表达也有一定程度的增加。结论 在受到伤害性疼痛刺激时除了脊髓背角，感受疼痛、应激及做出防御反应的相应脑区也会被活化，表达FOS蛋白。

Objective To investigate the expression profiles of FOS protein in the mice brain subregions induced by subcutaneous formalin injection to one hindpaw. Methods After adult mice received an injection of 5% formalin in the hindpaw, their spontaneous pain behaviors were recorded within 60min. The expression, distribution and number of FOS-positive neurons in the ipsilateral dorsal horn and supraspinal regions were detected by immunohistochemical assay at two hours after formalin injection. Results These mice showed their biting/licking time and flinches in a typical two-phase manner within 60min. The immunohistochemical staining results showed that FOS-positive neurons were significantly increased in the ipsilateral spinal cord, paraventricular nucleus, medial dorsal thalamic nucleus, anterior cingulate cortex, insular cortex and amygdala. Meanwhile, the expression of FOS protein in the dentate gyrus of hippocampus was also slightly increased. Conclusion Not only spinal dorsal horn but also subregions sensitive to pain and stress, will be activated functionally to mediate defensive response when mice are exposed to nociceptive stimuli.