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目的:评价海马miRNA320 (miR-320)在小鼠围术期认知障碍(PND)中的作用。方法:选择清洁级健康雄性C57/BL小鼠75只，12～14周龄，体重20～30 g，采用随机数字表法分为5组(n n＝15)：对照组(C组)、PND组、生理盐水对照组(NS组)、miR-320激动剂组(AG组)和miR-320抑制剂组(AT组)。采取异氟烷麻醉下行胫骨骨折内固定术制备小鼠PND模型。造模前2 h时NS组海马区注射生理盐水2 μl，AG组海马区注射miR-320激动剂agomir-320 2 μl , AT组海马区注射miR-320抑制剂antagomir-320 2 μl。分别于术前1 d和术后1、3、7 d时行Morris水迷宫实验(首次到达原平台时间及靶象限停留时间百分比)和旷场实验(运动路程)。分别于术后1、3和7 d时各随机处死5只小鼠，取海马组织，采用qRT-PCR法检测miR-320的表达。n 结果:与C组相比，PND组、NS组、AG组和AT组术后各时点首次到达原平台时间延长，靶象限停留时间百分比降低，PND组和NS组术后1和3 d时、AG组术后各时点海马组织miR-320表达上调，AT组术后1 d时海马组织miR-320表达上调，术后3和7 d时海马组织miR-320表达下调(n P0.05)。n 结论:海马miR-320表达上调参与了小鼠PND的过程。“,”Objective:To evaluate the role of hippocampal miRNA320 (miR-320) in perioperative neurocognitive disorders (PND) in mice.Methods:Seventy-five healthy male C57/BL mice, aged 12-14 weeks, weighing 20-30 g, were divided into 5 groups (n n = 15 each) using a random number table method: control group (group C), PND group, normal saline control group (NS group), miR-320 agonist group (group AG) and miR-320 inhibitor group (group AT). PND model was established by internal fixation of tibial fracture under isoflurane anesthesia.At 2 h before establishing the model, normal saline 2 μl was injected into the hippocampal area in group NS, miR-320 agonist agomir-320 2 μl was injected into the hippocampal area in group AG, and miR-320 inhibitor antagomir-320 2 μl was injected into the hippocampal area in group AT.Morris water maze test (the first time to reach the original platform, percentage of time of staying at the target quadrant) and open field test (travel distance) were performed at 1 day before operation and 1, 3 and 7 days after operation.Five mice were randomly sacrificed at 1, 3 and 7 days after operation, and hippocampal tissues were taken for determination of the expression of miR-320 by quantitative real-time polymerase chain reaction.n Results:Compared with group C, the first time to reach the original platform was significantly prolonged, and the percentage of time of staying at the target quadrant was decreased at each time point after operation in PND, NS, AG, and AT groups, the miR-320 expression at 1 and 3 days after operaiton in PND and NS groups and at each time point after operation in group AG was significantly up-regulated, and the miR-320 expression was significantly up-regualted at 1 day after operaiton and down-regulated at 3 and 7 days after operaiton in group AT (n P0.05).n Conclusion:Up-regulation of miR-320 expression in hippocampus is involved in the process of PND in mice.