艾司氯胺酮对丙泊酚麻醉致发育期大鼠远期认知功能障碍的影响及PI3K/Akt信号通路在其中的作用

Effect of esketamine on long-term cognitive dysfunction induced by propofol anesthesia in developing rats and the role of PI3K/Akt signaling pathway

目的评价艾司氯胺酮对丙泊酚麻醉致发育期大鼠远期认知功能障碍的影响及磷脂酰肌醇3-激酶(PI3K)/丝氨酸-苏氨酸激酶(Akt)信号通路在其中的作用。方法清洁级健康SD大鼠48只,雌雄不拘,7日龄,体质量10~15 g,采用随机数字表法分为4组(n=12):脂肪乳剂组(C组)、丙泊酚组(P组)、艾司氯胺酮+丙泊酚组(EP组)和PI3K抑制剂LY294002+艾司氯胺酮+丙泊酚组(LYEP组)。C组腹腔注射中/长链脂肪乳注射液100 mg/kg;P组腹腔注射丙泊酚50 mg/kg,待大鼠翻正反射恢复后(40~60 min),再追加丙泊酚50 mg/kg;EP组腹腔注射艾司氯胺酮10 mg/kg,随后再给予丙泊酚,方法同P组;LYEP组经侧脑室注射LY29400225μg,30 min后腹腔注射艾司氯胺酮10 mg/kg,随后给予丙泊酚,方法同P组。于苏醒后2 h时,每组随机处死6只大鼠,采用HE染色法检测海马神经元病理学结果,采用Western blot法检测海马组织Akt、磷酸化Akt(p-Akt)、Bax和cleaved caspase-3的表达。剩余6只大鼠于出生后30 d时采用Y迷宫实验评估学习记忆能力。结果与C组比较,P组、EP组和LYEP组海马组织p-Akt/Akt比值降低,Bax和cleaved caspase-3表达上调,学会所需训练次数增加,正确反应率降低(P<0.05),海马CA1区神经元发生病理学损伤;与P组比较,EP组和LYEP组海马组织p-Akt/Akt比值升高,Bax和cleaved caspase-3表达下调,学会所需训练次数减少,正确反应率升高(P<0.05),海马CA1区神经元病理学损伤减轻;与EP组比较,LYEP组海马组织p-Akt/Akt比值降低,Bax和cleaved caspase-3表达上调,学会所需训练次数增加,正确反应率降低(P<0.05),海马CA1区神经元病理学损伤加重。结论艾司氯胺酮可减轻丙泊酚致发育期大鼠远期认知功能障碍,其机制与激活PI3K/Akt信号通路,抑制神经元凋亡有关。

Objective To evaluate the effect of esketamine on long-term cognitive dysfunction induced by propofol anesthesia in the developing rats and the role of phosphatidylinositol-3-kinase(PI3K)/serine-threonine protein kinase(Akt)signaling pathway.Methods Forty-eight clean-grade healthy Sprague-Dawley rats of either sex,aged 7 days,weighing 10-15 g,were divided into 4 groups(n=12 each)using a random number table method:fat emulsion group(C group),propofol group(P group),esketamine+propofol group(EP group),and PI3K inhibitor LY294002+esketamine+propofol group(LYEP group).Medium/long-chain fat emulsion injection 100 mg/kg was intraperitoneally injected in C group.Propofol was intraperitoneally injected at a dose of 50 mg/kg,followed by an additional dose of 50 mg/kg after the righting reflex was restored(40-60 min later)in P group.In group EP,esketamine 10 mg/kg was intraperitoneally injected,followed by propofol administration using the same method as previously described in P group.In LYEP group,LY29400225μg was injected via the lateral ventricle,30 min later ketamine 10 mg/kg was intraperitoneally injected,and then propofol was given using the same method as previously described in P group.Six rats in each group were randomly sacrificed at 2 h after emergence for microscopic examination of pathological changes of hippocampal neurons and for determination of Akt,phosphorylated Akt(p-Akt),Bax,and cleaved caspase-3 in the hippocampal tissues(using Western blot).The remaining 6 rats in each group were subjected to Y-maze test to evaluate their learning and memory abilities at 30 days after birth.The p-Akt/Akt ratio was calculated.Results Compared with C group,the p-Akt/Akt ratio in the hippocampal tissues was significantly decreased,the expression of Bax and cleaved caspase-3 was up-regulated,the number of training sessions required for learning was increased,the correct response rate was decreased(P<0.05),and the pathological damage to neurons in hippocampal CA1 region was found in P,EP and LYEP groups.Compared with P group,the p-Akt/Akt ratio in the hippocampal tissues was significantly increased,the expression of Bax and cleaved caspase-3 was down-regulated,the number of training sessions required for learning was decreased,the correct response rate was increased(P<0.05),and the pathological damage to neurons in hippocampal CA1 region was significantly attenuated in EP and LYEP groups.Compared with EP group,the p-Akt/Akt ratio in the hippocampal tissue was significantly decreased,and the expression of Bax and cleaved caspase-3 was up-regulated,the number of training sessions required for learning was increased,the correct response rate was decreased(P<0.05),and the pathological damage to neurons in hippocampal CA1 region was aggravated in LYEP group.Conclusions Esketamine can alleviate long-term cognitive impairment caused by propofol anesthesia in the developing rats,and the mechanism may be related to activation of the PI3K/Akt signaling pathway and inhibition of apoptosis in neurons.