目的 采用慢性注射糖皮质激素诱导的小鼠抑郁模型，观察逍遥散拆方药队（CDB）醋酸乙酯部位的抗抑郁作用，从调节下丘脑-垂体-肾上腺（hypothalamic-pituitary-adrenal，HPA）轴-神经可塑性关联角度探究其抗抑郁作用机制。方法 雄性ICR小鼠随机分为对照组、模型组、氟西汀（13.2 mg/kg）组、CDB水煎液（生药量22.0 g/kg）组和CDB醋酸乙酯部位低、高剂量（0.159、0.319 g/kg，即生药量11.0、22.0 g/kg）组，模型组和各给药组连续21 d ip地塞米松（10 mg/kg）建模，并同时给予相应药物。通过糖水偏好试验、飞溅试验、悬尾试验、强迫游泳试验与新颖抑制性喂养试验测试小鼠抑郁样行为；甲苯胺蓝染色法检测海马CA3区神经元尼氏小体数量；免疫荧光法标记海马齿状回（dentate gyrus，DG）区5-溴脱氧尿核苷（5-bromo-2′-deoxyuridine，Brdu）和双皮质素（doublecortin，DCX）阳性表达神经元；ELISA测定小鼠血清皮质酮（corticosterone，CORT）、促肾上腺皮质激素（adreno-cortico-tropic-hormone，ACTH）、促肾上腺皮质激素释放激素（corticotropin releasing hormone，CRH）和脑源性神经营养因子（brain-derived neurotrophic factor，BDNF）含量；Western blotting检测海马区磷酸化糖皮质激素受体（phosphorylated glucocorticoid receptor，pGR）/GR、血清和糖皮质激素调节蛋白激酶1（serum and glucocorticoid-inducible kinase 1，SGK1）、磷酸化磷脂酰肌醇3-激酶（phosphorylated phosphatidylinositol 3-kinase，p-PI3K）/PI3K、磷酸化蛋白激酶B（phosphorylated protein kinase B，p-Akt）/Akt、磷酸化哺乳动物雷帕霉素靶蛋白（phosphorylated mammalian target of rapamycin，p-mTOR）/mTOR、磷酸化酪氨酸激酶受体B（phosphorylated tyrosine kinase receptor B，p-TrkB）/TrkB、磷酸化环磷腺苷效应元件结合蛋白（phosphorylated cAMP-response element binding protein，p-CREB）/CREB、BDNF、突触生长蛋白（Synaptophysin）及突触后致密蛋白95（postsynaptic density protein 95，PSD95）蛋白表达。结果 CDB醋酸乙酯部位能明显提高模型小鼠的糖水偏好率和飞溅试验中的梳洗时间（P＜0.05、0.01），缩短悬尾试验和强迫游泳试验中的不动时间及新颖抑制性喂养试验的摄食潜伏期（P＜0.05、0.01）；显著提高模型小鼠海马CA3区神经元尼氏小体平均A值（P＜0.05、0.01），促进海马DG区Brdu和DCX表达（P＜0.05），并能提高Synaptophysin及PSD95蛋白表达水平（P＜0.05、0.01）；显著对抗模型小鼠血清中CORT、ACTH和CRH水平（P＜0.05、0.01），抑制HPA轴的过度激活；并下调海马区pGR/GR表达（P＜0.05、0.01），恢复GR对CORT的敏感性；显著上调模型小鼠海马组织p-PI3K/PI3K、p-Akt/Akt、p-mTOR/mTOR、p-TrkB/TrkB、p-CREB/CREB值及BDNF蛋白表达（P＜0.05、0.01）。结论 CD醋酸乙酯部位能通过恢复CORT/GR活性，抑制HPA轴的过度激活；并通过激活PI3K/Akt/mTOR及BDNF/TrkB/CREB信号通路，促进海马神经可塑性来减轻慢性注射糖皮质激素诱导的小鼠抑郁样行为。

Objective To study the antidepressant effect of ethyl acetate fraction of disassembled prescription of Xiaoyao San (逍遥散, CDB) in glucocorticoid-induced depression mice model by chronic injection, and investigate the mechanism of its antidepressant effect from the perspective of modulating the hypothalamic-pituitary-adrenal (HPA) axis-neuroplasticity association. Methods Male ICR mice were randomly divided into control group, model group, fluoxetine (13.2 mg/kg) group, CDB water decoction (raw dosage 22.0 g/kg) group, and CDB ethyl acetate fraction low- and high dose (0.159, 0.319 g/kg, raw dosage 11.0, 22.0 g/kg) groups. The model group and each administration group were continuously modeled with dexamethasone (10 mg/kg) for 21 d, and the corresponding drugs were given simultaneously. The mouse sucrose preference test, splash test, tail suspension test, forced swimming test and novel inhibitory feeding test were carried out to test depression-like behavior in mice; Toluidine blue staining was used to detect the number of neuronal Nissl bodies in CA3 region of hippocampus; Immunofluorescence was used to label hippocampal dentate gyrus (DG) 5-bromo-2′-deoxyuridine (Brdu) and doublecortin (DCX) positive expressions neurons; ELISA was used to determine corticosterone (CORT), adreno-cortico-tropic-hormone (ACTH), corticotropin releasing hormone (CRH) and brain-derived neurotrophic factor (BDNF) levels in serum of mice; The expressions of phosphorylated-glucocorticoid receptor (pGR)/GR, serum and glucocorticoid-inducible kinase 1 (SGK1), phosphorylated phosphatidylinositol 3-kinase (p-PI3K)/PI3K, phosphorylated protein kinase B (p-Akt)/Akt, phosphorylated mammalian target of rapamycin (p-mTOR)/mTOR, phosphorylated tyrosine kinase receptor B (p-TrkB)/TrkB, phosphorylated cAMP-response element binding protein (p-CREB)/CREB, BDNF, Synaptophysin and postsynaptic density protein 95 (PSD95) in hippocampus were measured by Western blotting. Results The ethyl acetate fraction of CDB significantly increased the sucrose preference rate and the grooming time of mice in the splash test (P < 0.05, 0.01), shortened the immobility time in the tail suspension test and forced swimming test and the feeding latency in the novel inhibitory feeding test in chronically injected corticosteroid-induced depressed mice (P< 0.05, 0.01); CDB ethyl acetate fraction significantly increased the mean optical density value of neuronal nisin in CA3 region of mouse hippocampus (P< 0.05, 0.01), promoted the expression of Brdu and DCX in DG region of hippocampus (P < 0.05), and significantly increased the expression levels of Synaptophysin and PSD95 protein (P < 0.05, 0.01); CDB ethyl acetate fraction significantly reversed the up-regulated CORT, ACTH and CRH levels in serum and inhibited the over-activation of HPA axis; CDB ethyl acetate fraction down-regulated pGR/GR expression in hippocampal region and restored the sensitivity of GR to CORT (P < 0.05, 0.01). CDB ethyl acetate fraction significantly upregulated the expression levels of p-PI3K/PI3K, p-AKT/AKT, p-mTOR/mTOR, p-TrkB/TrkB, p-CREB/CREB and BDNF proteins in hippocampal tissues of model mice (P < 0.05, 0.01). Conclusion The ethyl acetate fraction of CDB restores CORT/GR activity by inhibiting the hyperactivation of HPA axis, and attenuates chronic corticosterone-induced depression-like behavior in mice by activating PI3K/Akt/mTOR signaling pathway and BDNF/TrkB/CREB signaling pathway to promote hippocampal neuroplasticity.

国家自然科学基金资助项目（81503277）；国家自然科学基金资助项目（82074094）；四川省科技厅应用基础研究项目（2020YJ0388）；成都中医药大学西南特色中药资源国家重点实验室开放基金（2020XSGG002）