摘要目的:评价七氟烷麻醉诱发新生大鼠远期学习记忆能力障碍与突触后致密蛋白95(PSD-95)/Kalirin-7/Ras相关的C3肉毒杆菌毒素底物1(Rac1)信号通路的关系。方法:SPF级雄性Wistar大鼠60只，7日龄，体重12~18 g，采用随机数字表法为分为5组( n＝12)：对照组(C组)、1%七氟烷麻醉2 h组(S 1组)、1%七氟烷麻醉4 h组(S 2组)、2%七氟烷麻醉2 h组(S 3组)和2%七氟烷麻醉4 h组(S 4组)。麻醉后第4、8和12周行Morris水迷宫实验。末次Morris水迷宫实验完成后，处死大鼠，取海马组织，HE染色观察病理学结果，TUNEL染色计算神经元凋亡率，分别采用Western blot法和qRT-PCR法检测PSD-95、Kalirin-7和Rac1及其mRNA的表达。 结果:与C组比较，麻醉后第4、8和12周S 1组、S 2组、S 3组、S 4组逃避潜伏期延长，穿越原平台次数减少，目标象限停留时间缩短，海马神经元凋亡率升高，磷酸化Rac1/Rac1比值降低，PSD-95、Kalirin-7及其mRNA表达下调( P<0.05)；与S 4组比较，S 1组、S 2组、S 3组逃避潜伏期缩短，穿越原平台次数增多，目标象限停留时间延长，海马神经元凋亡率降低，磷酸化Rac1/Rac1比值升高，PSD-95和Kalirin-7及其mRNA表达上调( P<0.05)，海马组织病理改变程度减轻。 结论:七氟烷麻醉诱导新生大鼠远期学习记忆能力障碍的机制可能与抑制海马PSD-95/Kalirin-7/Rac1信号通路活性有关。

abstractsObjective:To evaluate the relationship between long-term learning and memory impairment induced by sevoflurane anesthesia and postsynaptic density protein-95 (PSD-95)/Kalirin-7/Ras-related C3 botulinum toxin substrate 1 (Rac1) signaling pathway in neonatal rats.Methods:Sixty SPF male Wistar rats, aged 7 days, weighing 12-18 g, were divided into 5 groups ( n=12 each) using a random number table method: control group (group C), 1% sevoflurane anesthesia for 2 h group (group S 1), 1% sevoflurane anesthesia for 4 h group (group S 2), 2% sevoflurane anesthesia for 2 h group (group S 3) and 2% sevoflurane anesthesia for 4 h group (group S 4). Morris water maze test was performed at 4, 8 and 12 weeks after anesthesia.The rats were sacrificed after the last Morris water maze test, and the hippocampal tissues were obtained for microscopic examination of the pathological changes (using HE staining), neuron apoptosis (by TUNEL staining), and expression of PSD-95, Kalirin-7 and Rac1 protein and mRNA (by Western blot and quantitative real-time polymerase chain reaction). The apoptosis rate was calculated. Results:Compared with group C, the escape latency was significantly prolonged, the number of crossing the original platform was reduced, the time of stay in the target quadrant was shortened, and the apoptosis rate of hippocampal neurons was increased at 4th, 8th and 12th weeks after anesthesia, phosphorylated Rac1/Rac1 ratio was decreased, and the expression of PSD-95 and Kalirin-7 protein and mRNA was down-regulated in S 1, S 2, S 3 and S 4 groups ( P<0.05). Compared with group S 4, the escape latency was significantly shortened, the number of crossing the original platform was increased, the time of stay in the target quadrant was prolonged, and the apoptosis rate of hippocampal neurons was decreased, phosphorylated Rac1/Rac1 ratio was increased, the expression of PSD-95 and Kalirin-7 protein and mRNA was up-regulated, and the histopathological changes of hippocampal tissues were attenuated in S 1, S 2 and S 3 groups ( P<0.05). Conclusions:The mechanism by which sevoflurane anesthesia induces long-term learning and memory impairment may be related to inhibition of activity of PSD-95/Kalirin-7/Rac1 signaling pathway in hippocampi of neonatal rats.