摘要目的：评价长时间机械通气对小鼠术后早期海马炎症反应的影响。方法健康雄性C57BL∕6小鼠48只，8~10周龄，体重20~25 g，采用随机数字表法分为3组（ n＝16）：正常对照组（ C组）、手术组（ O组）和术后长时间机械通气组（ MV组）。 O组和MV组行胫骨骨折切开复位内固定术，O组术后吸入异氟醚麻醉6 h；MV组术后异氟醚麻醉下机械通气6 h。于机械通气结束后1、3 d时取8只小鼠，进行恐惧条件化实验，以评价认知功能，计算僵直时间比率；随后取静脉血样和海马组织，采用ELISA法检测血浆和海马IL?6、TNF?α和IL?1β的水平。结果与C组比较，O组机械通气结束后僵直时间比率降低，血浆和海马IL?6、TNF?α和IL?1β的水平升高（P＜0．01）；与O组比较， MV组机械通气结束后僵直时间比率降低，血浆和海马IL?6、TNF?α和IL?1β的水平升高（ P＜0．01）。结论长时间机械通气导致小鼠术后早期认知功能障碍的机制与诱发海马炎症反应有关。

abstractsObjective To evaluate the effect of long?time mechanical ventilation on early postoper?ative inflammatory responses in the hippocampi of mice. Methods Forty?eight healthy male C57BL∕6 mice, aged 8-10 weeks, weighing 20-25 g, were divided into 3 groups ( n=16 each) using a random number table: control group ( group C) , operation group ( group O) and long?time mechanical ventilation after operation group ( group MV) . Open reduction and internal fixation was performed after tibial fracture was induced in O and MV groups. Group O inhaled isoflurane for 6 h after operation. The mice were me?chanically ventilated for 6 h under isoflurane anesthesia in group MV. On 1 and 3 days after the end of ven?tilation, 8 mice were randomly selected, and contextual fear conditioning test was carried out to assess the cognitive function. The rate of time spent freezing was calculated. Then venous blood samples were collected and hippocampi removed for determination of the levels of interleukin?6 ( IL?6) , tumor necrosis factor?al?pha ( TNF?α) and IL?1β in plasma and hippocampal tissues by enzyme?linked immunosorbent assay. Re?sults Compared with group C, the rate of time spent freezing was significantly decreased, and the levels of IL?6, TNF?α and IL?1β in plasma and hippocampal tissues were significantly increased after the end of ventilation in group O ( P<0.01) . Compared with group O, the rate of time spent freezing was significantly decreased, and the levels of IL?6, TNF?α and IL?1β in plasma and hippocampal tissues were significantly increased after the end of ventilation in group MV ( P<0.01) . Conclusion The mechanism by which long?time mechanical ventilation leads to early postoperative cognitive dysfunction is related to induction of in?flammatory responses in the hippocampi of mice.