The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), 36 Mingxin Road, Guangzhou 510370, PR China; Guangzhou University of Traditional Chinese Medicine, 16 Airport Road, Guangzhou 510405, PR China.
The Affiliated Brain Hospital of Guangzhou Medical University (Guangzhou Huiai Hospital), 36 Mingxin Road, Guangzhou 510370, PR China.
J Ethnopharmacol. 2018 Mar 25;214:13-21. doi: 10.1016/j.jep.2017.11.037. Epub 2017 Dec 5.
Xiaoyao San (XYS) is a classic Chinese herbal formula for treatment of depression. The present study aimed to investigate the antidepressant effects of XYS in a rat model of chronic unpredictable mild stress (CUMS) and the underlying mechanisms.
A CUMS rat model of depression was established via 4 weeks of unpredictable stimulation. Then the rats were orally administered paroxetine and XYS for 2 weeks with continued stress. Behavioral assessments, including an open field test (OFT), sucrose preference test (SPT) and forced swim test (FST), were conducted to evaluate the antidepressant effects of XYS. The concentrations in rat plasma of tryptophan (Trp) and its metabolic products, including kynurenine (Kyn) and quinolinic acid (QUIN), were determined using high performance liquid chromatography tandem mass spectrometry with electrochemical detection (HPLC-MS/MS). The mRNA and protein levels in rat hippocampus of depression-related brain derived neurotrophic factor (BDNF), cyclic AMP response element binding protein (CREB) and nerve cell adhesion molecule (NCAM) were determined by real-time qPCR and Western blot, respectively. Enzyme Linked Immunosorbent Assay (ELISA) was used to detect the activities of indoleamine 2,3-dioxygenase (IDO) and kynurenine-3-monooxygenase (KMO) in rat plasma.
The results showed that a successful CUMS rat model was established through 4 weeks of continuous unpredictable stimulation, as indicated by the significant decrease in locomotor activity and increase in immobility time in the OFT, reduction in body weight and food intake etc. Compared with the normal group, the concentrations of Kyn and QUIN had significantly (p < 0.05) decreased at day 28 in the control group, but then improved after drug treatment with paroxetine and XYS. There were no obvious changes in the activities of IDO and KMO. Compared with the normal group, the mRNA of NCAM, CREB and BDNF were significantly down-regulated (p < 0.001) in the control group, BDNF gene was up-regulated by paroxetine or XYS treatment, NCAM and CREB gene did not change in XYS group, protein expressions of BDNF and CREB were significantly increased, and NCAM was significantly reduced (p < 0.05).
XYS reversed the abnormalities of the tryptophan-kynurenine metabolic pathways in depressed rats and achieved an excellent antidepressant effect. Its direct impact may be observed as changes in biological indicators in rat hippocampus tissue.
逍遥散（XYS）是一种经典的中药方剂，用于治疗抑郁症。本研究旨在探讨 XYS 在慢性不可预测轻度应激（CUMS）大鼠模型中的抗抑郁作用及其机制。
通过 4 周的不可预测刺激建立抑郁大鼠 CUMS 模型。然后，大鼠继续给予应激并口服给予帕罗西汀和 XYS 治疗 2 周。采用旷场试验（OFT）、糖水偏好试验（SPT）和强迫游泳试验（FST）进行行为评估，以评价 XYS 的抗抑郁作用。采用高效液相色谱-串联质谱联用电化学检测法（HPLC-MS/MS）测定大鼠血浆中色氨酸（Trp）及其代谢产物犬尿氨酸（Kyn）和喹啉酸（QUIN）的浓度。采用实时 qPCR 和 Western blot 分别测定大鼠海马中与抑郁相关的脑源性神经营养因子（BDNF）、环磷腺苷反应元件结合蛋白（CREB）和神经细胞黏附分子（NCAM）的 mRNA 和蛋白水平。酶联免疫吸附试验（ELISA）检测大鼠血浆中吲哚胺 2,3-双加氧酶（IDO）和犬尿氨酸-3-单加氧酶（KMO）的活性。
结果表明，通过连续 4 周的不可预测刺激成功建立了 CUMS 大鼠模型，OFT 中大鼠的运动活性显著降低，不动时间增加，体重和食物摄入量减少等。与正常组相比，对照组第 28 天时 Kyn 和 QUIN 浓度显著降低（p < 0.05），但用帕罗西汀和 XYS 治疗后有所改善。IDO 和 KMO 的活性无明显变化。与正常组相比，对照组 NCAM、CREB 和 BDNF 的 mRNA 明显下调（p < 0.001），帕罗西汀或 XYS 治疗可上调 BDNF 基因，XYS 组 NCAM 和 CREB 基因无变化，BDNF 和 CREB 蛋白表达显著增加，NCAM 显著减少（p < 0.05）。
XYS 逆转了抑郁大鼠色氨酸-犬尿氨酸代谢途径的异常，取得了良好的抗抑郁效果。其直接影响可能表现在大鼠海马组织中生物标志物的变化。
