鲍　冲， 金　哲， 柯剑娟， 陈　凯， 王焱林

(武汉大学中南医院， 湖北 武汉　430071)



右美托咪定对单肺通气大鼠术后早期空间记忆功能的影响*

鲍冲， 金哲， 柯剑娟， 陈凯， 王焱林**

(武汉大学中南医院， 湖北 武汉430071)

目的： 探讨右美托咪定对单肺通气大鼠术后早期空间记忆能力的影响。方法： 选择雄性SD大鼠72只，月龄10～11月，随机分为双肺通气组(TLV组)、单肺通气组(OLV组)和右美托咪定组(DEX组)；DEX组于诱导前30 min腹腔注射盐酸右美托咪定25 μg/kg，TLV组与OLV组给予等量生理盐水腹腔注射；各组大鼠采用异氟烷诱导并维持麻醉，经口气管插管，TLV组全程双肺通气，OLV组和DEX组双肺通气5 min后采用插入过深法行单肺通气，90 min后恢复双肺通气30 min；每组各取6只大鼠，行右颈内静脉、左侧颈总动脉逆血流置管，以开始单肺通气0、30、60、90和120 min时 (分别记作T0、T1、T2、T3、T4)采集右颈内静脉和左侧颈总动脉血行血气分析，计算脑氧摄取率(CERO2)；各组剩余18只大鼠，于术前5 d开始每天行Morris水迷宫定向航行训练，并于术后第1 、3 、7 天时行空间探索实验，记录各组大鼠逃避潜伏期、目标象限停留时间和穿台次数。结果： 随着术后通气时间延长，各组CERO2逐渐上升(P<0.01)，OLV组在T1至T4时点CERO2明显高于TLV组(P<0.01)，恢复双肺通气后，仍高于TLV组；DEX组在T1至T4时点CERO2均明显低于OLV组(P<0.05或P<0.01)；各组大鼠随着术前训练天数的增加，逃避潜伏期逐渐缩短(P<0.01)；OLV组在术后第 1、3、7 天，逃避潜伏期均较TLV组明显延长(P<0.01)，目标象限停留时间缩短(P<0.01)，穿台次数减少(P<0.01)；DEX组在术后第 1、3、7 天逃避潜伏期均短于OLV组，且目标象限停留时间增加，穿台次数增加(P<0.05)。结论： 右美托咪定可以改善单肺通气大鼠术后早期空间记忆功能，其机制可能与降低脑组织氧耗有关。

右美托咪定； 单肺通气； 脑氧摄取率； 认知功能障碍

[Abstract]Objective: To investigate the effect of Dexmedetomidine on the early spatial memory function in rats undergoing one-lung ventilation surgery. Methods: 72 male sprague-dawley rats were randomly divided into 3 groups with 24 of each: group of two-lung ventilation (group TLV)，group of one-lung ventilation(group OLV) and group of one-lung ventilation accompanied with the injection of Dexmedetomidine(group DEX). Group DEX received Dexmedetomidine by intraperitoneal injection with a dose of 25 μg/kg in 30 minutes before induction, while an equal volume of saline was given to group TLV and group OLV at the same time. All three groups receive isoflurane anesthesia (with a flow of 1.5%), two-lung ventilation were given for 5min after intubation for each group followed by one-lung ventilation for 90min and lung inflate for 30min for group OLV and group DEX while only two-lung ventilation were given for group TLV. 6 rats of each group were chosen randomly to capture blood samples from left carotid artery and right internal jugular vein at the time of the beginning(T0), 30 min(T1), 60 min(T2)，90 min (T3) of one-lung ventilation and 30 min after lung inflate (T4) for blood gas analysis to calculate CERO2. The remaining rats in each group were divided randomly into 3 subgroups with 6 of each. The spatial memory function was evaluated by Morris Water Maze(MWM). The place navigation test was taken for five consecutive day before ventilation. The 3 subgroups had the spatial probe test respectively on 1, 3 or 7 post-operative day (post-1d, post-3d, post-7d) for detecting escape latency(EL), percentage of time spend in target quadrant and times of cross over the platform. Results: CERO2in every groups increased gradually while ventilation. Compared with group TLV, CERO2increased significantly at T1、T2、T3、T4in group OLV(P<0.01) . Compared with group OLV, CERO2were lower in group DEX at T1、T2、T3、T4(P<0.05 orP<0.01). EL shortened gradually in each training day(P<0.01) and no difference among groups. Compared with group TLV, EL prolonged in group OLV at 1、3、7 post-operative days(P<0.01). Compared with group OLV, EL shortened, times of cross over the platform and percentage of time spend in target quadrant enhanced at 1、3、7 postoperative days in group DEX (P<0.05 orP<0.01). Conclusions: Dexmedetomidine improves early spatial memory function in rats undergoing one-lung ventilation, the mechanism may be related with reducing oxygen consumption in the brain.

[Key words]dexmedetomidine; one-lung ventilation; cerebral oxygen uptake rates; cognitive dysfunction

术后认知功能障碍(postoperative cognitive dysfunction,POCD)表现为麻醉和手术后出现的学习、空间记忆等功能的减退，早期术后认知功能障碍通常指术后1周内出现的认知功能减退，可延长住院日，增加医疗负担，近年来在临床受到重视。POCD的发生机制复杂，可能涉及到神经炎性反应及脑氧供需平衡失调[1-2]。单肺通气……