Objectives: To explore the damage effects of chronic restraint stress (CRS) on amygdala cells through the rat CRS model.
Methods: The rat CRS model was established, and the changes in body weight and adrenal mass in control group and CRS group were monitored at 1 d, 7 d, 14 d and 21 d. The behavior changes were evaluated by the percentage of retention time of open arms and open arm entries using the elevated plus maze (EPM). ELISA was used to detect the concentrations of rat's corticotropin releasing hormone (CRH), adrenocorticotropic hormone (ACTH) and cortisol. The changes of expression of glucocorticoid receptor (GR) and glial fibrillary acidic protein (GFAP) in amygdala were determined by immunohistochemistry and Western blotting. Ultrastructure changes of glial cell were observed by transmission electron microscopy. The apoptosis rate of amygdala was measured by flow cytometry.
Results: Compared with the control group at the same time points, body weight of CRS 1 d, 7 d, 14 d and 21 d groups increased slowly, but adrenal mass increased significantly; the serum level of CRH, cortisol and ACTH increased significantly at 7 d, 14 d and 21 d respectively; the expression of GR in amygdala was increased while that of GFAP was decreased; EPM test suggested that the percentage of retention time of open arms and open arm entries decreased significantly after 14 d. The CRS group showed different degrees of glial cell damage in amygdala, and the apoptosis rate of glial cell was significantly increased in 21 d group.
Conclusions: This study successfully established a CRS model in rats, and anxiety-like behavioral changes in model rats may be caused by apoptosis of amygdala astrocytes.
目的: 通过建立大鼠慢性束缚应激（chronic restraint stress，CRS）模型，观察CRS对大鼠杏仁核细胞的损伤结果。方法: 建立大鼠CRS模型，监测对照组和CRS组（1 d、7 d、14 d、21 d）大鼠体质量及肾上腺质量的变化，并应用高架十字迷宫实验计算开臂停留时间百分比及进入开臂次数百分比评价大鼠行为学变化。使用ELISA检测大鼠血清促肾上腺皮质激素释放激素（corticotropin releasing hormone，CRH）、促肾上腺皮质激素（adrenocorticotropic hormone，ACTH）和皮质醇的浓度。应用免疫组织化学及Western印迹法检测杏仁核糖皮质激素受体（glucocorticoid receptor，GR）和胶质纤维酸性蛋白（glial fibrillary acidic protein，GFAP）表达的变化。通过透射电镜观察杏仁核胶质细胞的超微结构改变。使用流式细胞术检测杏仁核细胞凋亡率。结果: CRS 1 d组、7 d组、14 d组和21 d组大鼠与相同时间点对照组相比，体质量增加缓慢，肾上腺质量明显增加；血清CRH于7 d开始明显升高，皮质醇自14 d开始明显升高，ACTH于21 d明显升高；杏仁核GR表达增加，而GFAP表达明显降低；高架十字迷宫实验发现，14 d开始大鼠开臂停留时间百分比及进入开臂次数百分比明显减少。CRS组大鼠杏仁核脑区呈现不同程度的胶质细胞损伤性变化，21 d组杏仁核神经胶质细胞凋亡率显著增加。结论: 本研究成功建立了大鼠CRS损伤模型，模型大鼠出现的焦虑样行为学改变很可能源于杏仁核星形胶质细胞的凋亡。.
Keywords: Western blotting; amygdala; animal model; apoptosis; chronic restraint stress; elevated plus maze; enzyme linked immunosorbent assay; forensic pathology; rats.