Department of Anesthesiology, Nanshi Hospital Affiliated to Henan University, Nanyang, China.
Department of Neurosurgery, The Second Affiliated Hospital of Xuzhou Medical University, Xuzhou, China.
J Appl Toxicol. 2022 Apr;42(4):617-628. doi: 10.1002/jat.4243. Epub 2021 Sep 22.
Isoflurane, a common volatile anesthetic, has been widely used to provide general anesthesia in operations. However, exposure to isoflurane may cause widespread neurotoxicity in the developing animal brain. Fraxetin, a natural coumarin derivative extracted from the bark of Fraxinus rhynchophylla, possesses versatile pharmacological properties including anti-oxidative, anti-inflammatory, and neuroprotective effects. However, the effect and action mechanism of fraxetin on neurotoxicity induced by isoflurane are unknown. Reactive oxygen species (ROS) generation, cell viability, lactate dehydrogenase (LDH) release, and apoptosis were estimated by 2',7'-dichlorofluorescin-diacetate (DCFH-DA) staining, MTT, LDH release, and terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end-labeling (TUNEL) staining assays, respectively. The protein levels of light chain 3 (LC3)-I, LC3-II, p62, protein kinase B (Akt), and phosphorylated Akt (p-Akt) were detected by western blot analysis. Isoflurane induced ROS, LDH release, apoptosis, and autophagy, but inhibited the viability in HT22 cells, which were overturned by fraxetin or ROS scavenger N-acetyl-L-cysteine. Fraxetin suppressed isoflurane-induced PI3K/Akt inactivation in HT22 cells. PI3K/Akt inactivation by LY294002 resisted the effects of fraxetin on isoflurane-induced autophagy and autophagy-modulated neurotoxicity in HT22 cells. In conclusion, fraxetin suppressed ROS-dependent autophagy by activating the PI3K/Akt pathway to inhibit isoflurane-induced neurotoxicity in hippocampal neuronal cells.
异氟醚是一种常用的挥发性麻醉剂，广泛用于手术中的全身麻醉。然而，暴露于异氟醚可能会导致发育中动物大脑的广泛神经毒性。瑞香素，一种从秦皮中提取的天然香豆素衍生物，具有多种药理学特性，包括抗氧化、抗炎和神经保护作用。然而，瑞香素对异氟醚诱导的神经毒性的作用和作用机制尚不清楚。通过 2'，7'-二氯荧光素二乙酸酯（DCFH-DA）染色、MTT、LDH 释放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）染色测定活性氧（ROS）生成、细胞活力、乳酸脱氢酶（LDH）释放和细胞凋亡。通过 Western blot 分析检测轻链 3（LC3）-I、LC3-II、p62、蛋白激酶 B（Akt）和磷酸化 Akt（p-Akt）的蛋白水平。异氟醚诱导 ROS、LDH 释放、细胞凋亡和自噬，但抑制 HT22 细胞的活力，而瑞香素或 ROS 清除剂 N-乙酰-L-半胱氨酸则逆转了这种情况。瑞香素抑制 HT22 细胞中 PI3K/Akt 的失活。LY294002 抑制 PI3K/Akt 失活可抵抗瑞香素对异氟醚诱导的自噬和自噬调节的 HT22 细胞神经毒性的影响。总之，瑞香素通过激活 PI3K/Akt 通路抑制 ROS 依赖性自噬，从而抑制海马神经元细胞中异氟醚诱导的神经毒性。
