星形胶质细胞活化在心理应激影响大鼠咬肌痛觉敏感中的作用

摘要

目的：探讨心理应激状态下咬肌痛觉敏感增高现象与三叉神经脊束核尾侧亚核（Vc ）内星形胶质细胞活化的关系。方法：健康雄性SD大鼠40只，随机分为：空白对照组和应激3、7、14 d组（n＝10），实验组大鼠经束缚应激相应时间后，采用旷场实验和高架十字迷宫实验观察各组大鼠焦虑、抑郁样情绪；Von Frey丝刺激检测各组大鼠咬肌的机械性痛阈；免疫组化染色和Western-blot检测Vc内星形胶质细胞活化标志物神经胶质酸性蛋白（GFAP）表达的变化。结果：①束缚应激7、14 d组大鼠在旷场中央停留时间和中央活动总路程，以及在高架十字迷宫开放臂中的滞留时间百分比和进入开放臂次数百分比均较空白对照组明显降低（P＜0．05）；②束缚应激7、14 d组大鼠咬肌机械性痛阈均较空白对照组明显降低（P＜0．05）；③束缚应激7、14 d 组大鼠Vc内GFAP的表达阳性率及其蛋白的表达水平均明显高于空白对照组（P＜0．05）。结论：慢性束缚造成的心理应激能导致Vc内星形胶质细胞的活化，可能参与了心理应激导致的咬肌痛觉敏感性的增高。%AIM:To investigate the role of astrocyte activation in the spinal trigeminal nucleus caudalis (Vc)in the increased masseter mechanical sensitivity induced by psychological stress in rats.METHODS:40 male SD rats were randomly divided into a control group and 3 stress groups (n=10).The rats in stress groups were treated by constraint for 3,7 and 14 days respectively.The stressed condition was testified by open field test and the elevated plus maze test.Von Frey filaments were used to evaluate the mechanical sensitivity of masseter.The expression of glial fibrillary acidic protein (GFAP)was measured by immunohistochemistry and Western-blot.RESULTS:The rats in the 7-and 14-day stress groups showed significant anxious and depressive behavior(P<0.05 ),and increase of masseter mechanical sensitivity(P<0.05).GFAP expression in Vc was increased in the stress groups compared with that in the control group (P<0.05 ).CONCLUSION:Chronic restraint stress can result in astrocytes activation in Vc that may contribute to the increased masseter mechanical sensitivity in rats.