七氟烷对大鼠近期空间回忆能力、海马APOE、Aβ 表达的影响

Impact of Sevoflurane on short-term spatial memory capacity and expressions of APOE and amyloid beta in hippocampus of rats

摘要:

目的 探讨七氟烷对成年大鼠近期空间回忆能力及海马载脂蛋白E（APOE）、β 淀粉样蛋白（Aβ）表达的影响。方法 成年SD 大鼠54 只，随机分为七氟烷麻醉组、运载气体组、空白对照组，每组54 只。七氟烷麻醉组吸入3.2% 七氟烷+ 运载气体（1 L/min 氧气O2+1 L/min 空气）2 h，运载气体组吸入运载气体2 h，空白对照组自然饲养。模型复制前、取材前行Morris 水迷宫实验。模型复制后第1 天（T1）、第3 天（T3）、第7 天（T7）取脑组织，采用免疫组织化学法检测海马CA1 区、CA3 区、DG 区APOE、Aβ 的平均光密度值（MOD）。结果 ①与运载气体组比较，各时间点七氟烷麻醉组穿越原平台次数、进入原平台象限次数、原平台象限滞留时间、原平台象限滞留时间百分比比较，差异无统计学意义（P >0.05）。②与运载气体组比较，T1、T3 时间点七氟烷麻醉组大鼠海马各区APOE 的MOD 值降低（P <0.05），T7 时间点七氟烷麻醉组大鼠海马各区Aβ 的MOD 值增高（P <0.05）。结论 3.2% 七氟烷不损害成年大鼠近期空间回忆能力。3.2% 七氟烷吸入麻醉后1 周内，通过下调APOE 表达，抑制海马Aβ 沉积；麻醉后第7 天是海马Aβ 增加的关键时间点。

Abstract:

Objective To investigate the impact of Sevoflurane on spatial memory capacity and expressions of apolipoprotein E (APOE) and amyloid beta (Aβ) in hippocampus of adult rats. Methods Fifty-four adult rats were randomly divided into sev group, con group and blank group. The rats in the sev group inhaled 3.2% Sevoflurane and carrier gas (1L/min O2 plus 1L/min air) for 2 h, those in the con group inhaled carrier gas for 2 h and those in the blank group were bred naturally. In all rats Morris Water Maze experiment was done before modeling and sampletaking.Brain tissues were taken on the 1st day (T1), 3rd day (T3) and 7th day (T7) after modeling, then the levels of mean optical density (MOD) of APOE and Aβ in the CA1, CA3 and DG areas of hippocampus were measured by immunohistochemistry (IHC). Results There was no significant difference between the con group and the sev group in the times across the original platform, the times onto original platform quadrant, the retention time in the original platform quadrant or the percentage of the time retaining in the original platform quadrant at each time point(P > 0.05). Compared with the con group, APOE MOD in each hippocampal area of the sev group reduced at T1 and T3 (P < 0.05), Aβ MOD in each hippocampal area of the sev group increased at T7 (P < 0.05). Conclusions 3.2% Sevoflurane does not damage short-term spatial memory ability of adult rats. 3.2% Sevoflurane inhalation anesthesia inhibits Aβ deposition in hippocampus through down-regulation of APOE expression within 1 week; the 7th day after Sevoflurane anesthesia is a key point for Aβ increase in hippocampus.