目的 探讨淫羊藿苷对慢性温和不可预知应激（CUMS）构建抑郁样行为小鼠的影响及对Toll样受体4/髓样分化因子88/核因子κB（TLR4/MyD88/NF-κB）通路的调节作用。方法 药效实验：12只小鼠作为对照组，其余小鼠经CUMS构建抑郁症模型，连续3周。第4周进行糖水偏好测试，将糖水偏好率≤75%的小鼠认定为模型构建成功，随机分为模型组和淫羊藿苷高、中、低剂量(120、40、10 mg·kg^-1)组，每组12只。淫羊藿苷经0.5%羧甲基纤维素钠溶解后ig给药，连续21 d，期间持续造模，对照组与模型组小鼠ig 0.5%羧甲基纤维素钠。机制研究：8只小鼠作为对照组，剩余小鼠进行CUMS造模，取24只模型构建成功小鼠，分为模型组、淫羊藿苷(120 mg·kg^-1)组、淫羊藿苷(120 mg·kg^-1)+GSK1795091(TLR4激动剂，每只0.1μg经鼻滴给药，10μg·mL^-1、每只10μL)组。经糖水偏好测试、旷场测试、悬尾测试与强迫游泳测试，评价动物抑郁样行为；小鼠处死后取全脑组织，经苏木精-伊红（HE）染色评价脑组织病理结构改变；取海马组织，通过酶联免疫吸附试验（ELISA）试剂盒检测海马中白细胞介素-6（IL-6）、白细胞介素-1β（IL-1β）、肿瘤坏死因子-α（TNF-α）水平，Western blotting检测Toll样受体4（TLR4）信号通路相关蛋白表达。结果 与对照组相比，模型组小鼠蔗糖水偏好率显著减少（P<0.05），旷场测试中穿格次数显著减少（P<0.05），悬尾不动时间与强迫游泳不动时间显著增加（P<0.05）,HE染色显示大量细胞呈现萎缩、肿胀、坏死或异型核状态，ELISA检测显示脑组织中IL-6、IL-1β与TNF-α水平显著增加（P<0.05）,Western blotting检测显示TLR4、髓样分化因子（MyD88）蛋白与磷酸化核因子κB（p-NF-κB）蛋白表达显著上调（P<0.05）；与模型组相比，淫羊藿苷高、中剂量小鼠蔗糖水偏好率显著增加（P<0.05），旷场测试穿格次数显著增加（P<0.05），悬尾与强迫游泳不动时间显著减少（P<0.05），神经细胞大小和形状逐渐恢复正常，萎缩、肿胀、坏死或异型核细胞减少，海马组织中IL-6、IL-1β与TNF-αs水平显著减少（P<0.05）,TLR4、MyD88与p-NF-κB蛋白表达显著下调（P<0.05），淫羊藿苷低剂量组各项指标没有明显变化。与淫羊藿苷高剂量组相比，淫羊藿苷(120 mg·kg^-1)+GSK1795091组蔗糖水偏好率显著减少（P<0.05），悬尾与强迫游泳不动时间显著增加（P<0.05），旷场测试中穿格次数显著减少（P<0.05）；此外，炎症细胞因子IL-6、IL-1β与TNF-α水平显著增加（P<0.05）。结论 淫羊藿苷可能通过抑制TLR4/MyD88/NF-κB通路活化，调节免疫炎症反应，在小鼠体内发挥抗抑郁作用。

Objective To explore the effects of icariin（ICA） on the depression-like behavior in mice induced by chronic unpredictable mild stress（CUMS） and its regulatory role in the toll-like receptor 4/myeloid differentiation factor 88/nuclear factor κB（TLR4/MyD88/NF-κB） pathway. Methods Pharmacodynamic experiment: 12 mice were used as the control group, and the remaining mice were subjected to CUMS to establish a depression model for 3 consecutive weeks. In the 4 th week, a sucrose preference test was conducted. Mice with a sucrose preference rate ≤ 75% were considered to have successfully established the model and were randomly divided into the model group and the icaritin high-, medium-, and low-dose(120, 40, and 10 mg·kg^-1) groups, with 12 mice in each group. Icaritin was dissolved in 0.5% sodium carboxymethyl cellulose and administered ig for 21 consecutive days. During this period, the model was continuously established. Mice in the control group and the model group were ig administered 0.5% sodium carboxymethyl cellulos. Mechanism study: 8 mice were used as the control group, and the remaining mice were subjected to CUMS to establish a model. 24 successfully established model mice were selected and divided into the model group, the icaritin(120 mg·kg^-1) group, and the icaritin(120 mg·kg^-1) + GSK1795091(TLR4 agonist, 0.1 μg per mouse, 10 μg·mL^-1, 10 μL per mouse) group. The sucrose preference test, open field test, tail suspension test, and forced swimming test were conducted to evaluate the depressive-like behaviors of the animals. After the mice were sacrificed, the whole brain tissue was taken and stained with hematoxylin-eosin（HE） to evaluate the pathological structure changes of the brain tissue. The hippocampal tissue was taken, and the levels of interleukin-6（IL-6）, interleukin-1β（IL-1β）, and tumor necrosis factor-α（TNF-α） in the hippocampus were detected by enzyme-linked immunosorbent assay（ELISA） kits. The expression of proteins related to the toll-like receptor 4（TLR4） signaling pathway was detected by Western blotting. Results In the pharmacodynamics study, compared with the control group, the sucrose preference of the CUMS group was decreased（P < 0.05）, the crossing number of open field test were decreased（P < 0.05）, the immobility time of tail suspension and forced swimming were increased（P < 0.05）, and HE staining revealed that a large number of neurons exhibited atrophy, swelling, necrosis, or abnormal nuclear morphology, the contents of IL-6, IL-1β and TNF-α in hippocampal tissue were increased（P < 0.05）, and the expression of TLR4, MyD88 and p-NF-κB protein were up-regulated（P < 0.05）. Compared with the CUMS group, the sucrose preference rate was increased（P < 0.05）, the scores of open field test were increased（P < 0.05）, the immobility time of tail suspension and forced swimming were decreased（P < 0.05） in the ICA-H and ICA-M group, as well as HE staining showed that the size and shape of neurons gradually returned to normal, with a decrease in atrophic, swollen, necrotic, or cells with abnormal nuclei, and the contents of IL-6, IL-1β and TNF-α in brain were decreased（P < 0.05）, the expression of TLR4, MyD88 and p-NF-κB protein were downregulated（P < 0.05）. However, there were no significant changes in all parameters in ICA-L group. In the mechanism research, compared with the ICA-H group, the sucrose preference rate of the ICA-H+A group was decreased（P < 0.05）, and the scores of open field test were decreased（P < 0.05）, the immobility time of tail suspension and forced swimming tests were increased（P<0.05）. In addition, the levels of inflammatory cytokines IL-6, IL-1β and TNF-α were increased（P < 0.05）. Conclusion ICA may regulate the immune inflammatory response by inhibiting the activation of TLR4/MyD88/NF-κB signaling pathway and play an antidepressant role in mice.

R285.5

福建省科技计划项目(2021Y0099)