Department of Anesthesiology, Second Affiliated Hospital of Nanchang University.
Biol Pharm Bull. 2020 Jun 1;43(6):938-945. doi: 10.1248/bpb.b19-00790. Epub 2020 Mar 19.
The neurodevelopmental toxicity of isoflurane has been proved by many studies, which makes it essential to explore the underline mechanisms and search for protective agents to attenuate its neurotoxcity. Accumulating evidence showed that L-theanine had neuroprotective effects on injured neurons and the developing brain. The present study was designed to investigate whether L-theanine could attenuate isoflurane-induced damage in neural stem cells and cognitive impairment in young mice, and to discuss the role of protein kinase B (Akt)-glycogen synthase kinase 3β (GSK-3β) signaling pathway in this process. Multipotential neural stem cells (NSCs) and C57BL/6J mice were treated with either gas mixture, isoflurane, or L-theanine 30 min prior to isoflurane exposure, respectively. NSC viability was detected by CCK-8 assay. NSC proliferation and apoptosis were assessed by immunofluorescence and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL) assay, respectively. The levels of cleaved caspase-3 and phosphorylated (p)-Akt and p-GSK-3β in NSCs were tested by Western blotting. Cognitive function of mice was tested by Morris Water Maze at postnatal day (P) 30-35. The results indicated that isoflurane exposure inhibited NSC viability and proliferation, promoted NSC apoptosis as well as increased caspase-3 activation and down-regulated the expressions of p-Akt and p-GSK-3β in NSCs, and that isoflurane exposure on neonatal mice would induce late cognitive impairment. Pretreatment with L-theanine could attenuate isoflurane-caused damage in NSCs and cognitive deficits in young mice. Addinonally, the protective effects of L-theanine on isoflurane-injured NSCs could be reversed by Akt inhibitor Triciribine. Our data showed that pretreatment with L-theanine eliminated the NSC damage and cognitive impairment induced by isoflurane exposure, and that the neuroprotective effect of L-theanine was associated with the Akt-GSK-3β signaling pathway.
异氟醚的神经发育毒性已被多项研究证实，因此有必要探索其潜在机制并寻找保护剂来减轻其神经毒性。越来越多的证据表明，L-茶氨酸对受损神经元和发育中的大脑具有神经保护作用。本研究旨在探讨 L-茶氨酸是否可以减轻神经干细胞中异氟醚诱导的损伤和幼年小鼠的认知障碍，并讨论蛋白激酶 B（Akt）-糖原合成酶激酶 3β（GSK-3β）信号通路在这一过程中的作用。多潜能神经干细胞（NSCs）和 C57BL/6J 小鼠分别用混合气体、异氟醚或 L-茶氨酸处理 30 分钟，然后再进行异氟醚暴露。通过 CCK-8 检测 NSC 活力。通过免疫荧光和末端脱氧核苷酸转移酶介导的脱氧尿苷三磷酸缺口末端标记（TUNEL）检测 NSC 增殖和凋亡。通过 Western blot 检测 NSCs 中 cleaved caspase-3 和磷酸化（p）-Akt 和 p-GSK-3β的水平。在出生后第 30-35 天通过 Morris 水迷宫测试小鼠的认知功能。结果表明，异氟醚暴露抑制 NSC 活力和增殖，促进 NSC 凋亡，增加 caspase-3 活化，下调 NSCs 中 p-Akt 和 p-GSK-3β 的表达，异氟醚暴露于新生小鼠会引起晚期认知障碍。L-茶氨酸预处理可减轻 NSCs 中异氟醚引起的损伤和幼年小鼠的认知缺陷。此外，Akt 抑制剂 Triciribine 可逆转 L-茶氨酸对异氟醚损伤的 NSCs 的保护作用。我们的数据表明，L-茶氨酸预处理消除了异氟醚暴露引起的 NSC 损伤和认知障碍，L-茶氨酸的神经保护作用与 Akt-GSK-3β 信号通路有关。
