金钗石斛水提物通过调节APP/PS1小鼠突触可塑性及胶质细胞激活缓解学习记忆损伤

Water extract of Dendrobium nobile Lindl. alleviates learning and memory impairment through synaptic plasticity modulation and glial cell activation in APP/PS1 mice

摘要:

目的 探讨金钗石斛水提物（dendrobium nobile lindl，DNL）是否能通过调节突触的可塑性缓解APP/PS1阿尔茨海默病（Alzheimer’s disease，AD）模型小鼠的学习记忆损伤。方法 12只野生型C57BL/6雄性小鼠随机分成两组（n=6）：对照组（WT），单纯DNL处理组（WT＋DNL）：DNL（10 mg/kg，灌胃，每天1次，持续2个月）；12只APP/PS1小鼠分为2组：APP/PS1 AD模型组（APP/PS1）和APP/PS1 AD模型治疗组（APP/PS1+DNL）：APP/PS1小鼠7个月龄时给予DNL（10 mg/kg，灌胃，每天1次，持续2个月）。Morris水迷宫检测小鼠记忆能力；高尔基染色法检测小鼠脑海马区树突棘数量；海马脑片电生理检测长时程增强（long term potentiation，LTP）；免疫组织化学技术检测海马区胶质纤维酸性蛋白（glial fibrillary acidic protein，GFAP）及离子钙接头蛋白（Ionized calcium-binding adapter molecule 1，Iba1）的表达量以评估胶质细胞数量。Western blot检测小鼠海马区Synapsin I、Synatophysin、IL-6、TNF-α及IL-1β蛋白的表达量。结果 与WT组相比，APP/PS1组小鼠在第2~6天时逃避潜伏期的时间明显增加，表现出学习和记忆功能障碍。与WT组相比，APP/PS1组小鼠脑组织的树突棘数量和突触相关蛋白Synapsin I、Synatophysin的表达量减少，星型胶质细胞和小胶质细胞的数量和炎症因子的表达量明显增加。DNL治疗明显改善了小鼠的学习和记忆功能障碍，抑制了APP/PS1小鼠树突棘的丢失及突触相关蛋白Synapsin I、Synatophysin的减少，缓解了海马CA1区神经元的LTP损伤，增加了海马区星型胶质细胞及小胶质细胞的数量，显著下调了炎症因子IL-6、TNF-α及IL-1β蛋白的表达水平。结论 金钗石斛水提物通过抑制APP/PS1小鼠突触长时程增强缓解学习和记忆功能障碍。

Abstract:

Objective To explore whether the water extract of Dendrobium nobile Lindl.（DNL） can alleviate learning and memory impairment through synaptic plasticity modulation in APP/PS1 Alzheimer’s disease（AD） model in mice.Methods Twelve wild-type（WT） C57BL/6 male mice were randomly divided into two groups（n=6）：WT control group（WT） and DNL treatment alone group（WT+DNL，DNL was intragastrically administered at 10 mg/kg，once a day，for 2 months）. Twelve APP/PS1 mice were divided into two groups：APP/PS1 AD model group（APP/PS1） and APP/PS1 AD model treatment group（APP/PS1+DNL，APP/PS1 mice aged seven months received DNL intragastrically administered at 10 mg/kg，once a day，for two months）. Morris water maze was used to test the memory ability of the mice；Gorky staining was used to determine the number of dendritic spines in the hippocampus of the brain in the mice；electroencephalography was used to measure the long-term potentiation（LTP） in the hippocampus of the brain； immunohistochemical techniques were used to measure the expression of glial fibrillary acidic protein and ionized calcium-binding adaptor molecule 1 in the hippocampus and evaluate the number of glial cells. The protein expression levels of Synapsin I，Synaptophysin，interleukin-6（IL-6），tumor necrosis factor-α（TNF-α），and interleukin-1β（IL-1β） in the hippocampus of the mice were measured by western blot.Results Compared with the WT group，the APP/PS1 group had a significantly increased escape latency on days 2-6，showing learning and memory dysfunction. In addition，compared with the WT group，the APP/PS1 group showed reductions in the number of dendritic spines and the expression levels of synapse-related proteins Synapsin I and Synaptophysin but noticeable increases in the number of astrocytes and microglial cells and the expression levels of inflammatory factors in the brain tissue. However，DNL treatment improved learning and memory function，inhibited the loss of dendritic spines and the decreases in synapse-related proteins Synapsin I and Synaptophysin in the APP/PS1 mice，alleviated the LTP injury of neurons in the hippocampal CA1 area，increased the numbers of astrocytes and microglial cells，and significantly downregulated the protein expression levels of inflammatory factors IL-6，TNF-α，and IL-1β.Conclusion The water extract of DNL may alleviate learning and memory dysfunction by inhibiting synaptic LTP in APP/PS1 mice.