七氟醚对神经元缺氧损伤的保护及其作用机制

Protective effects and mechanisms of sevoflurane on anoxia injuryin cultured rat hippocampal neurons

目的观察七氟醚对大鼠海马神经元缺氧损伤的保护作用及其机制。方法用原代培养的新生大鼠海马神经细胞建立缺氧模型,用MTT法测定神经元存活率。采用激光扫描共聚焦显微镜动态监测单个海马神经元[Ca^2＋]i随缺氧或加入KCl前后的实时变化。结果七氟醚在2MAC（肺泡气最小有效浓度）,可降低神经元缺氧损伤时的细胞死亡率（P〈0.05）。0.5～2MAC七氟醚能抑制缺氧及50mmol/LKCl引起的[Ca^2＋]i升高（P〈0.05）。结论七氟醚对离体大鼠海马神经元缺氧性损伤具有保护作用,其机制可能与七氟醚抑制缺氧引起[Ca^2＋]i异常升高有关。

Objective To investigate the protective effects and its mechanism of sevoflurane on cultured rat hippocampal neurons subjected to anoxia injury. Methods Hippocampal neurons of neonatal rat which had been cultttred in vitro for 10 days, were divided into control groups and sevoflurane treatment group. The neurons were exposed to oxygen-glucose deprivation for 24 h. The cell survival rate in each group was evaluated by MTT colorimetry. The effect of sevoflurane on neuronal calcium overload evoked by anoxia or 50 mmol/L KCl or 1 mmol/L glutamate was observed. The fluo-3, a fluorescent probe, was used for imaging intracellular calcium and laser scanning confocal microscope（LSCM） was used to measure real-time changes of [Ca^2＋ ]i in cultured rat hippocampal neurons. Results The hippocampal neurons developed acute neuronal swelling and wide spread neuronal degeneration following anoxia for 24 h. Sevoflurane at concentration of 2MAC obviously relieved the neuronal injury （ P 〈 0.05）. Sevoflurane at concentration of 0.5 - 2MAC significantly inhibited [ Ca^2＋ ] i elevation caused by anoxia or KCl which induced the opening of the voltage gated calcium ion channels（ P 〈 0.05）.2MAC sevoflurane inhibited [Ca^2＋ ]i elevation caused by glutamate, an agonist of the N-methyl-D-aspartate （NMDA）receptor（ P 〈 0.01）. Conclusion Sevoflurane could effectively protect cultured hippocampal neurons from anoxia injury. The mechanism may be partially due to the inhibition of [ Ca^2＋ ] ioverload via the voltage-gated calcium ion channels and the NMDA receptor calcium ionchannels.