Abstract：
OBJECTIVE: The aim of this study was to investigate the role of depolarizing activation of Na+-Ca2+ exchanger (NCX) by oligodendrocyte progenitor cells (OPC) in the effect of sevoflurane on myelination.
METHODS: On postnatal days 7, 8, and 9, mice were exposed to 3 % sevoflurane for 2 h per day. The proliferation, differentiation, and myelin sheath of OPC were observed with immunofluorescence, quantitative real-time polymerase chain reaction (QRT-PCR), and transmission electron microscopy (TEM) at various time points. The open field, Y maze, and new object recognition tests were used to measure spatial learning and memory. siRNA was used for the knockdown NCX1 in human OPC (HOPC) before sevoflurane exposure; the Transwell migration assay was used to measure cell migration ability and Fluo 4-AM was used to measure intracellular Ca2+ concentration.
RESULTS: Pretreatment with an NCX inhibitor attenuated the proliferation and differentiation of OPC induced by sevoflurane and induced a remarkable increase in platelet-derived growth factor receptor-alpha (PDGFRα), 2, 3-cyclic nucleotide 3-phosphodiesterase (CNPase), oligodendrocyte transcription factor 2 (Olig2), and homeodomain protein NK2 homeobox 2 (NKX2.2) levels. Pretreatment with an NCX inhibitor alleviated the sevoflurane-induced myelination disorder and cognitive impairment. The decreased cell migration and increased intracellular Ca2+ concentration observed in the siRNA-negative control group was reversed in the sevoflurane plus siRNA-NCX1 group.
CONCLUSIONS: This study suggests that repeated sevoflurane exposure in newborn mice leads to depolarization of OPC, which leads to Ca2+ influx through NCX and affects OPC proliferation, migration, differentiation, and myelination, ultimately leading to cognitive impairment.
METHODS: On postnatal days 7, 8, and 9, mice were exposed to 3 % sevoflurane for 2 h per day. The proliferation, differentiation, and myelin sheath of OPC were observed with immunofluorescence, quantitative real-time polymerase chain reaction (QRT-PCR), and transmission electron microscopy (TEM) at various time points. The open field, Y maze, and new object recognition tests were used to measure spatial learning and memory. siRNA was used for the knockdown NCX1 in human OPC (HOPC) before sevoflurane exposure; the Transwell migration assay was used to measure cell migration ability and Fluo 4-AM was used to measure intracellular Ca2+ concentration.
RESULTS: Pretreatment with an NCX inhibitor attenuated the proliferation and differentiation of OPC induced by sevoflurane and induced a remarkable increase in platelet-derived growth factor receptor-alpha (PDGFRα), 2, 3-cyclic nucleotide 3-phosphodiesterase (CNPase), oligodendrocyte transcription factor 2 (Olig2), and homeodomain protein NK2 homeobox 2 (NKX2.2) levels. Pretreatment with an NCX inhibitor alleviated the sevoflurane-induced myelination disorder and cognitive impairment. The decreased cell migration and increased intracellular Ca2+ concentration observed in the siRNA-negative control group was reversed in the sevoflurane plus siRNA-NCX1 group.
CONCLUSIONS: This study suggests that repeated sevoflurane exposure in newborn mice leads to depolarization of OPC, which leads to Ca2+ influx through NCX and affects OPC proliferation, migration, differentiation, and myelination, ultimately leading to cognitive impairment.
摘要：
目的：本研究的目的是研究少突胶质祖细胞（OPC）对Na+-Ca2+交换剂（NCX）的去极化激活在七氟醚对髓鞘形成作用中的作用。
方法：在出生后第7、8和9天，小鼠每天暴露于3％七氟醚2小时。扩散,分化,用免疫荧光法观察OPC的髓鞘，定量实时聚合酶链反应（QRT-PCR），和透射电子显微镜（TEM）在不同的时间点。开放的领域，Y迷宫,新的物体识别测试被用来测量空间学习和记忆。在七氟烷暴露之前，使用siRNA在人OPC（HOPC）中敲低NCX1；使用Transwell迁移测定来测量细胞迁移能力，并使用Fluo4-AM来测量细胞内Ca2浓度。
结果：用NCX抑制剂预处理减弱七氟醚诱导的OPC增殖和分化，并诱导血小板衍生生长因子受体α（PDGFRα）的显着增加，2，3-环核苷酸3-磷酸二酯酶（CNPase），少突胶质细胞转录因子2(Olig2),和同源异型结构域蛋白NK2同源异型盒2(NKX2.2)水平。NCX抑制剂预处理可减轻七氟醚诱导的髓鞘形成障碍和认知障碍。在siRNA阴性对照组中观察到的细胞迁移减少和细胞内Ca2+浓度增加在七氟醚加siRNA-NCX1组中被逆转。
结论：这项研究表明，新生小鼠反复暴露七氟醚会导致OPC去极化，这导致Ca2+通过NCX流入并影响OPC增殖，迁移,分化,和髓鞘形成，最终导致认知障碍。
方法：在出生后第7、8和9天，小鼠每天暴露于3％七氟醚2小时。扩散,分化,用免疫荧光法观察OPC的髓鞘，定量实时聚合酶链反应（QRT-PCR），和透射电子显微镜（TEM）在不同的时间点。开放的领域，Y迷宫,新的物体识别测试被用来测量空间学习和记忆。在七氟烷暴露之前，使用siRNA在人OPC（HOPC）中敲低NCX1；使用Transwell迁移测定来测量细胞迁移能力，并使用Fluo4-AM来测量细胞内Ca2浓度。
结果：用NCX抑制剂预处理减弱七氟醚诱导的OPC增殖和分化，并诱导血小板衍生生长因子受体α（PDGFRα）的显着增加，2，3-环核苷酸3-磷酸二酯酶（CNPase），少突胶质细胞转录因子2(Olig2),和同源异型结构域蛋白NK2同源异型盒2(NKX2.2)水平。NCX抑制剂预处理可减轻七氟醚诱导的髓鞘形成障碍和认知障碍。在siRNA阴性对照组中观察到的细胞迁移减少和细胞内Ca2+浓度增加在七氟醚加siRNA-NCX1组中被逆转。
结论：这项研究表明，新生小鼠反复暴露七氟醚会导致OPC去极化，这导致Ca2+通过NCX流入并影响OPC增殖，迁移,分化,和髓鞘形成，最终导致认知障碍。
