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目的:探讨醒脑静注射液(Xingnaojing,XNJ)预处理对七氟烷(sevoflurane)麻醉小鼠海马中突触结合蛋白-Ⅰ表达的影响及与学习记忆的相关性。方法:60只成年雄性C57BL/6小鼠经Morris水迷宫训练4d后,随机分为对照组、模型组、1ml/kg、5ml/kg和10ml/kg醒脑静组。采用3%七氟烷持续吸入6h建立七氟烷麻醉小鼠模型,给药组于麻醉前2h分别给予醒脑静1ml/kg、5ml/kg和10ml/kg腹腔注射,模型组于相同时间点给予生理盐水10ml/kg腹腔注射。麻醉结束12h后,应用Morris水迷宫测试小鼠的学习记忆能力,应用Realtime PCR分析突触结合蛋白-Ⅰ(synaptotagmin-Ⅰ,Syt-Ⅰ)mRNA的表达,应用免疫荧光法分析Syt-Ⅰ蛋白的表达情况,应用脑片LTP检测分析小鼠海马中的突触可塑性变化。结果:醒脑静预处理(10ml/kg)可明显改善小鼠的空间学习记忆能力,减少逃避潜伏期、增加穿越平台次数,提示醒脑静对七氟烷诱导的小鼠认知功能损伤有明显的改善作用。进一步的机制研究表明醒脑静预处理(10ml/kg)可增强小鼠海马组织中Syt-Ⅰ的蛋白和mRNA表达水平;同时,能明显提高兴奋性突触后电位(excitatory postsynaptic potential,EPSP)斜率相对值(%)。结论:醒脑静能够有效提高七氟烷麻醉后小鼠海马中Syt-Ⅰ的表达水平,调节突触可塑性,改善其学习记忆功能,且作用呈一定的剂量依赖性。
Objective: To investigate the effect of Xingnaojing (XNJ) preconditioning on the expression of synaptophysin-Ⅰ in hippocampus of sevoflurane-anesthetized mice and its relationship with learning and memory. Methods: Sixty adult male C57BL / 6 mice were randomly divided into control group, model group, 1ml / kg, 5ml / kg and 10ml / kg xingnaojing group after being trained by Morris water maze for 4 days. Sevoflurane anesthetized mice were established by continuous inhalation of 3% sevoflurane for 6 hours. The rats in the treatment group were given intracerebroventricular injection of 1 ml / kg, 5 ml / kg and 10 ml / kg respectively 2 hours before anesthesia. At the same time point Give normal saline 10ml / kg intraperitoneal injection. Twelve hours after the end of anesthesia, Morris water maze was used to test the learning and memory abilities of mice. Realtime PCR was used to analyze the expression of synaptotagmin-Ⅰ (Syt-Ⅰ) mRNA. The expression of Syt-Ⅰ protein was detected by immunofluorescence The changes of synaptic plasticity in the hippocampus of mice were analyzed by LTP assay. Results: Xingnaojing preconditioning (10ml / kg) can significantly improve the spatial learning and memory ability of mice, reduce the escape latency and increase the number of crossing the platform, suggesting that Xingnaojing has significant cognitive impairment on sevoflurane-induced mice The improvement effect. Further mechanism studies showed that xingnaojing preconditioning (10ml / kg) can enhance the expression of Syt-Ⅰprotein and mRNA in hippocampus of mice, and at the same time, significantly increase excitatory postsynaptic potential (EPSP) Relative value of slope (%). Conclusion: Xingnaojing can effectively increase the expression of Syt-Ⅰ in the hippocampus of mice after sevoflurane anesthesia, regulate the synaptic plasticity, and improve the learning and memory function in a dose-dependent manner.