褪黑素对异氟烷麻醉大鼠术后IL-6水平及认知功能的影响

Effect of Melatonin on IL-6 Level and Cognitive Function of Rats under Isoflurane Anesthesia

目的探索褪黑素(Melatonin)对异氟烷麻醉大鼠术后IL-6水平及认知功能的影响。方法选取36只雄性SD大鼠,根据随机数字表法分为异氟烷褪黑素组(NML组)、异氟烷组(NS组),同时设置正常大鼠为对照组(N组),每组各12只。NML组给予8 mg/kg褪黑素灌胃,NS组给予等体积羧甲基纤维素钠(Carboxymethylcellulose sodium,CMC)灌胃,N组灌胃等体积的生理盐水,1次/d,持续1周。三组均在异氟烷全麻吸入下行气管插管建立假手术模型,麻醉维持2 h。测定术后1~5 d大鼠的游泳平均速度;于术前1 d、术后1~5 d进行Morris水迷宫实验测得逃避潜伏期、准确跨越平台次以及目标象限停留时间百分比,并于术后第6天测试其记忆能力;于术前1 d、术后1 d、3 d、5 d采集各组大鼠尾静脉血1 mL,ELISA法检测IL-6水平。结果三组大鼠术后的游泳速度无显著差异(P>0.05);与N组和NS组相比,NML组的逃避潜伏期缩短、准确跨越平台次数以及目标象限停留时间百分比增加(P<0.05);术后1 d、3 d、5 d IL-6水平降低,差异有统计学意义(P<0.05);与NS组相比,术后1 d、3 d、5 d NML组IL-6水平下降,差异具有统计学意义(P<0.05),与术前1 d相比,NS组和NML组术后1 d、3 d、5 d IL-6水平显著升高(P<0.05)。结论褪黑素可以降低IL-6水平,进而改善老年大鼠术后认知功能障碍的发生。

Objective To explore the effect of Melatonin on the level of IL-6 and cognitive function in rats after isoflurane anesthesia.Methods Thirty-six male SD rats were selected and divided into isoflurane-melatonin group(NML group)and isoflurane group(NS group)according to the random number table.At the same time,normal rats were set as control group(N group).Group of 12 each.The NML group was given 8 mg/kg melatonin by gavage,the NS group was given an equal volume of Carboxymethylcellulose sodium(CMC)by gavage,and the N group was given an equal volume of normal saline once a day for 1 week,the three groups were all under general isoflurane anesthesia with tracheal intubation to establish a sham operation model,and anesthesia was maintained for 2 hours.Measure the average swimming speed of rats 1~5 days after operation;Morris water maze test was performed 1 day before operation and 1~5 days after operation to measure the escape latency,accurate crossing platform times,and the percentage of residence time in the target quadrant.The memory ability was tested on the sixth day after the operation;1 mL of tail vein blood of each group was collected 1 d before operation,1 d,3 d,and 5 d after operation,and IL-6 level was detected by ELISA.Results There was no significant difference in the swimming speed of the three groups of rats after surgery(P>0.05);compared with the N group and the NS group,the NML group had a shorter escape latency,accurate crossing of platforms and an increase in the percentage of stay time in the target quadrant(P<0.05);IL-6 levels decreased at 1 d,3 d,5 d after operation,and the difference was statistically significant(P<0.05);compared with the NS group,the IL-6 levels of the NML group at 1 d,3 d,and 5 d after operation Decrease,the difference was statistically significant(P<0.05).Compared with 1 day before operation,IL-6 levels in NS group and NML group were significantly increased at 1 d,3 d,and 5 d after operation(P<0.05).Conclusion Melatonin can reduce the level of IL-6,thereby improving the occurrence of postoperative cognitive dysfunction in aged rats.