Graduate School, Dentistry (Department of Anesthesiology), Osaka Dental University, Osaka, Japan.
Eur J Pharmacol. 2012 Jan 30;675(1-3):40-6. doi: 10.1016/j.ejphar.2011.11.040. Epub 2011 Dec 7.
To assess whether sevoflurane preconditioning is associated with inhibition of mitochondrial permeability transition pore (MPTP), the effects of sevoflurane were compared with those of cyclosporine A, a known inhibitor of MPTP opening. Isolated perfused guinea pig hearts underwent 30 min global ischemia and 120 min reperfusion (control). Sevoflurane preconditioning was elicited by administration of 2% sevoflurane for 10 min with 10 min washout before ischemia (sevoflurane). A preconditioning-like cardioprotection was also induced by administering cyclosporine A (0.2 μM) for 15 min, starting 5 min before ischemia and for 10 min after the onset of reperfusion (cyclosporine A). Left ventricular developed and end-diastolic pressures, coronary flow and infarct size were measured. Expressions of Akt and glycogen synthase kinase 3β (GSK3β), known mediators of inhibition of MPTP opening, were determined by Western blot analysis. GSK3β inhibition was achieved with LY294002. The effects of sevoflurane and cyclosporine A on calcium-induced MPTP opening in isolated calcein-loaded mitochondria were assessed. After ischemia-reperfusion, sevoflurane and cyclosporine A had higher left ventricular developed pressure. Infarct size was significantly reduced in sevoflurane and cyclosporine A vs. control. This was abolished by LY294002 in sevoflurane, but not in cyclosporine A. Akt and GSK3β phosphorylation after reperfusion were significantly increased in sevoflurane and cyclosporine A. Ca²⁺-induced reduction in calcein fluorescence was significantly attenuated in sevoflurane and cyclosporine A. Preconditioning agents, sevoflurane and cyclosporine A increase the threshold of calcium-induced MPTP opening to a similar extent. This effect by sevoflurane, but not cyclosporine A is at least partially mediated by GSK3β inactivation.
为了评估七氟醚预处理是否与抑制线粒体通透性转换孔（MPTP）有关，比较了七氟醚与环孢素 A 的作用，环孢素 A 是已知的 MPTP 开放抑制剂。分离的豚鼠心脏经历 30 分钟的整体缺血和 120 分钟的再灌注（对照）。七氟醚预处理通过给予 2%七氟醚 10 分钟，然后在缺血前用 10 分钟冲洗来诱发（七氟醚）。通过给予环孢素 A（0.2 μM）15 分钟，在缺血前 5 分钟开始，并在再灌注开始后 10 分钟，也可以诱导类似预处理的心脏保护作用（环孢素 A）。测量左心室发展和舒张末期压力、冠状动脉流量和梗塞面积。通过 Western blot 分析测定 Akt 和糖原合酶激酶 3β（GSK3β）的表达，Akt 和糖原合酶激酶 3β（GSK3β）是抑制 MPTP 开放的已知介质。用 LY294002 抑制 GSK3β。评估七氟醚和环孢素 A 对分离的钙加载线粒体中钙诱导的 MPTP 开放的影响。再灌注后，七氟醚和环孢素 A 的左心室发展压更高。与对照组相比，七氟醚和环孢素 A 的梗塞面积显著减少。在七氟醚中，这种作用被 LY294002 消除，但在环孢素 A 中没有。再灌注后，七氟醚和环孢素 A 中的 Akt 和 GSK3β 磷酸化明显增加。钙诱导的 calcein 荧光减少在七氟醚和环孢素 A 中明显减弱。预处理剂，七氟醚和环孢素 A，以相似的程度增加钙诱导的 MPTP 开放的阈值。七氟醚的这种作用，但不是环孢素 A 的作用，至少部分是由 GSK3β失活介导的。
