氯胺酮对新生鼠学习记忆功能的长期影响

目的研究氯胺酮麻醉对新生鼠成年后学习记忆功能的影响。方法12只出生1周SD大鼠，随机分为氯胺酮麻醉（Ket）组和生理盐水对照（Ns）组。Kct组腹腔注射50mg／kg氯胺酮；Ns组腹腔注射等量生理盐水。8周后利用Morris水迷宫进行定位航行实验和空间搜索实验，获取大鼠对水迷宫的学习和记忆获取能力以及对平台空间位置的记忆保持能力的相关数据，并行组间比较。制备大鼠海马脑片并行免疫组织化学染色，观察凋亡相关因子Bcl-2和Bax的表达。结果与Ns组比较，Ket组大鼠隐匿平台逃避潜伏期明显延长（P〈0．05）；穿越平台次数减少，活动总路径缩短（P〈0．05）。海马脑片观察显示，Ket组促凋亡因子Bax表达较Ns组明显；两组问抑凋亡因子Bcl-2表达无明显差异。结论在新生鼠的脑发育期使用氯胺酮，其成年后的学习记忆功能受损，其机制可能与海马区神经元凋亡有关。

Long-term effect of ketamine on learning and memory function of postnatal rats

Objective To investigate the effect of ketamine on learning and memory function of adult rats after injection of ketamine at early development stage. Methods Twelve rats born in a week were randomly divided into ketamine anesthesia group(Ket group)and normal saline control group(Ns group).Rats in Ket group were intraperitoneally injected with 50 mg/kg ketamine,and those in Ns group were administrated with same amount of normal saline.After eight weeks,Morris water maze test was adopted to explore the latency in place navigation and spatial probe ability.The sections of hippocampus were obtained,and immunohistochemical staining was employed to detect the expression of Bax and Bcl-2.Results In Morris water maze test,the latency in place navigation of Ket group Was significantly longer than that of Ns group(P<0.05),and the spatial probe ability significantly decreased(P<0.05).It Was revealed by immunohistochemical staining that the expression of Bax in Ket group was significantly higher than that in Ns group,while there was no significant difference in the expression of Bcl-2 between these two groups. Conclusion Application of ketamine in neonatal rats may result in learning and memory impairment in adulthood,and the underlying mechanism may correlate to the apoptosis of neuron in hippocampus region.