红景天苷对抑郁模型大鼠炎症反应和神经细胞凋亡的抑制作用及其机制

Inhibitory Effect and Its Mechanism of Salidroside on Inflammatory Response and Neuronal Apoptosis in Depression Model Rats

目的探讨红景天苷对慢性不可预测的轻度压力(CUMS)抑郁模型大鼠炎症反应和神经细胞凋亡的抑制作用及其机制。方法采用CUMS构建抑郁大鼠模型,第6~12周,红景天苷小、中、大剂量组大鼠分别腹腔注射红景天苷12.5,25,50 mg·kg^(-1),氟西汀组大鼠腹腔注射氟西汀5 mg·kg^(-1),H-89组大鼠鞘内注射2 mg·kg^(-1)H-89,正常对照组和模型对照组大鼠腹腔注射等量0.9%氯化钠溶液,均每天1次。记录大鼠体质量和蔗糖偏好。12周后,进行旷场实验、强迫游泳测试、莫里斯水迷宫实验。采用苏木精-伊红(HE)染色观察海马区神经损伤,流式细胞术检测神经细胞凋亡情况,酶联免疫吸附测定(ELISA)检测环磷酸腺苷(cAMP)、白细胞介素(IL)-6、IL-1β、肿瘤坏死因子-α(TNF-α)的含量;采用免疫印迹法检测cAMP依赖的蛋白激酶催化亚基-Ⅱα(PKAc-Ⅱα)和磷酸化环磷腺苷效应元件结合蛋白(p-CREB)/CREB蛋白表达水平。结果红景天苷干预后,CUMS大鼠体质量、蔗糖偏好率及旷场实验中行进距离、运动轨迹交叉次数、站立次数均明显增加;强迫游泳实验中不动时间、找到平台所需时间明显减少,60 s内找到平台次数明显增加;海马区神经细胞凋亡率及IL-1β、IL-6、TNF-α含量显著下降,海马组织中cAMP含量明显增加,PKAc-Ⅱα/β-actin和p-CREB/CREB蛋白表达明显上调;添加PKA抑制剂H-89后,能明显逆转红景天苷引起的CUMS大鼠上述变化。结论红景天苷可能通过cAMP/PKA/CREB信号通路抑制CUMS抑郁模型大鼠炎症反应和神经细胞凋亡。

Objective To investigate the inhibitory effect and its mechanism of salidroside on inflammatory response and neuronal apoptosis in depressed rats induced by chronic unpredictable mild stress(CUMS).Methods A depressed rat model was constructed by using CUMS.From week 6 to week 12,rats in the low,medium,and high dose of salidroside groups were intraperitoneally injected with 12.5,25,50 mg·kg^(-1)salidroside once a day;rats in the fluoxetine group were injected with 5 mg·kg^(-1)fluoxetine;rats in the normal control group and the model control group were injected with the same amount of 0.9%sodium chloride solution;and rats in the H-89 group were intrathecally injected with 2 mg·kg^(-1)H-89.Rat body mass and sucrose preference were recorded.Open field experiments,forced swimming tests,and Morris water maze were performed at 12 weeks.Neurological injury in the hippocampus was observed by hematoxylin-eosin(HE)staining.Neuronal apoptosis was detected by flow cytometry.The levels of cyclic adenosine monophosphate(cAMP),interleukin-6(IL-6),interleukin-1β(IL-1β)and tumor necrosis factor-α(TNF-α)were detected by enzyme linked immunosorbent assay(ELISA).The expression levels of cAMP-dependent protein kinase catalytic subunit-Ⅱα(PKAc-Ⅱα)and phosphorylated cAMP-response element binding protein(p-CREB)/CREB proteins were detected by Western blotting.Results After administration of salidroside,the weight of CUMS rats,the preference rate of syrup and the distance traveled in the open field experiment,the number of movement trajectories,and the number of standings increased significantly.The time required to force the swimming time and the time to find the platform is significantly reduced.The number of found platforms within 60 s has increased significantly.The neuronal apoptosis rate and the levels of IL-1β,IL-6 and TNF-αin hippocampus were significantly reduced.The content of cAMP in hippocampus increased significantly.The expression of PKAc-Ⅱα/β-actin and p-CREB/CREB protein was significantly up-regulated.Addition of PKA inhibitor H-89 can significantly reverse the above changes in CUMS rats caused by salidroside.Conclusion Salidroside may inhibit inflammatory response and neuronal apoptosis in CUMS-induced depression rats through cAMP/PKA/CREB signaling pathway.