氯胺酮麻醉及脾切除术对幼年大鼠学习记忆的影响

Effects of ketamine anesthesia and splenectomy on learning and memory of infancy rats

目的观察氯胺酮麻醉及脾切除术对幼年大鼠学习记忆的影响。方法健康幼年雄性SD大鼠30只,15日龄,体重29~31g,随机分为三组:生理盐水组(S组)、氯胺酮组(K组)、氯胺酮+脾切除组(KS组),三组大鼠腹腔分别给予等容量生理盐水0.3 ml、氯胺酮100 mg/kg(10mg/ml)、氯胺酮100mg/kg(10mg/ml),KS组大鼠氯胺酮麻醉后行脾切除。2周后三组大鼠进行Morris水迷宫实验,记录逃避潜伏期、Ⅱ象限穿越次数及Ⅱ象限游泳时间。水迷宫实验结束后杀死大鼠,采用ELISA法检测大鼠海马组织谷氨酸(Glu)和γ-氨基丁酸(GABA)含量。结果与S组比较,K组前3d和KS组前4d逃避潜伏期明显延长(P<0.01),K组和KS组Ⅱ象限穿越次数明显减少,Ⅱ象限游泳时间明显缩短(P<0.05);与K组比较,KS组逃避潜伏期明显延长,Ⅱ象限穿越次数明显减少,Ⅱ象限游泳时间明显缩短(P<0.01)。与S组比较,K组和KS组Glu含量明显降低,Glu/GABA明显减小(P<0.05),KS组GABA含量明显升高(P<0.05);与K组比较,KS组Glu含量明显降低,Glu/GABA明显减小(P<0.05)。结论氯胺酮麻醉及脾切除均能损伤幼年大鼠的学习记忆功能,且其记忆功能受损与海马区Glu含量及Glu/GABA下调有关。氯胺酮对幼年大鼠学习能力的损害只是暂时的,脾切除能延长并进一步损害幼年大鼠的学习能力。

Objective To investigate the effects of ketamine anesthesia and splenectomy on learning and memory of infancy rats.Methods Thirty healthy infancy male SD rats,aged 15 days,weighing 29-31 g,were equally randomized into three groups：saline group（group S）,ketamine group（group K）,ketamine and splenectomy group（group KS）.The three groups were administered a same volume of saline 0.3 ml,ketamine 100 mg/kg（10 mg/ml）,ketamine 100 mg/kg（10 mg/ml）separately.Rats in group KS carried out the splenectomy after the ketamine anesthesia.Morris water maze test was carried out after 2 weeks of the surgery,and the escape latency,the crossing numbers of theⅡ quadrant,as well as the times that rats swimming in theⅡ quadrant were recorded.Rats were killed after Morris water maze test,and the concentrations of Glu and GABA in the hippocampus were detected by ELISA test.Results Compared with group S,the escape latencies of group K before 3 dand group KS before 4 dwere longer （P〈0.01）.The crossing numbers of theⅡ quadrant in group K and group KS were lower,and the swimming times in theⅡquadrant were shorter（P〈0.05）.Compared with group K,the escape latency was longer,the crossing number,as well as the swimming time in theⅡ quadrant were reduced in group KS（P〈0.01）.Compared with group S,the glutamate concentrations in group K and group KS were lower,Glu/GABA were down-regulated（P〈0.05）,while the GABA concentration in group KS was increased（P〈0.05）;Compared with group K,the glutamate concentration in group KS was reduced and Glu/GABA were down-regulated（P〈0.05）.Conclusion Ketamine anesthesia and splenectomy were both impaired the learning and memory functions of the infancy rats,and the memory dysfunction was related with the changes of the glutamate concentrations and Glu/GABA downregulation in the hippocampus.Ketamine anesthesia impaired the learning function temporally,while the splenectomy prolonged and further impaired the learning function of the infancy rats.