Feng Jianhua, Lucchinetti Eliana, Ahuja Preeti, Pasch Thomas, Perriard Jean-Claude, Zaugg Michael
Institute of Anesthesiology, University Hospital Zurich, Zwitzerland.
Anesthesiology. 2005 Nov;103(5):987-95. doi: 10.1097/00000542-200511000-00013.
Postischemic administration of volatile anesthetics activates reperfusion injury salvage kinases and decreases myocardial damage. However, the mechanisms underlying anesthetic postconditioning are unclear.
Isolated perfused rat hearts were exposed to 40 min of ischemia followed by 1 h of reperfusion. Anesthetic postconditioning was induced by 15 min of 2.1 vol% isoflurane (1.5 minimum alveolar concentration) administered at the onset of reperfusion. In some experiments, atractyloside (10 microm), a mitochondrial permeability transition pore (mPTP) opener, and LY294002 (15 microm), a phosphatidylinositol 3-kinase inhibitor, were coadministered with isoflurane. Western blot analysis was used to determine phosphorylation of protein kinase B/Akt and its downstream target glycogen synthase kinase 3beta after 15 min of reperfusion. Myocardial tissue content of nicotinamide adenine dinucleotide served as a marker for mPTP opening. Accumulation of MitoTracker Red 580 (Molecular Probes, Invitrogen, Basel, Switzerland) was used to visualize mitochondrial function.
Anesthetic postconditioning significantly improved functional recovery and decreased infarct size (36 +/- 1% in unprotected hearts vs. 3 +/- 2% in anesthetic postconditioning; P < 0.05). Isoflurane-mediated protection was abolished by atractyloside and LY294002. LY294002 inhibited isoflurane-induced phosphorylation of protein kinase B/Akt and glycogen synthase kinase 3beta and opened mPTP as determined by nicotinamide adenine dinucleotide measurements. Atractyloside, a direct opener of the mPTP, did not inhibit phosphorylation of protein kinase B/Akt and glycogen synthase kinase 3beta by isoflurane but reversed isoflurane-mediated cytoprotection. Microscopy showed accumulation of the mitochondrial tracker in isoflurane-protected functional mitochondria but no staining in mitochondria of unprotected hearts.
Anesthetic postconditioning by isoflurane effectively protects against reperfusion damage by preventing opening of the mPTP through inhibition of glycogen synthase kinase 3beta.
挥发性麻醉药在缺血后给药可激活再灌注损伤挽救激酶并减少心肌损伤。然而，麻醉后处理的潜在机制尚不清楚。
将离体灌注的大鼠心脏暴露于40分钟的缺血，随后再灌注1小时。在再灌注开始时给予15分钟的2.1体积%异氟醚（1.5最低肺泡浓度）诱导麻醉后处理。在一些实验中，线粒体通透性转换孔（mPTP）开放剂苍术苷（10微摩尔）和磷脂酰肌醇3激酶抑制剂LY294002（15微摩尔）与异氟醚共同给药。在再灌注15分钟后，采用蛋白质印迹分析来测定蛋白激酶B/Akt及其下游靶点糖原合酶激酶3β的磷酸化情况。烟酰胺腺嘌呤二核苷酸的心肌组织含量用作mPTP开放的标志物。使用MitoTracker Red 580（Molecular Probes，Invitrogen，瑞士巴塞尔）的积累来观察线粒体功能。
麻醉后处理显著改善了功能恢复并减小了梗死面积（未保护心脏中为36±1%，而麻醉后处理中为3±2%；P<0.05）。苍术苷和LY294002消除了异氟醚介导的保护作用。如通过烟酰胺腺嘌呤二核苷酸测量所确定的，LY294002抑制了异氟醚诱导的蛋白激酶B/Akt和糖原合酶激酶3β的磷酸化并开放了mPTP。mPTP的直接开放剂苍术苷并不抑制异氟醚对蛋白激酶B/Akt和糖原合酶激酶3β的磷酸化，但逆转了异氟醚介导的细胞保护作用。显微镜检查显示线粒体示踪剂在异氟醚保护的功能性线粒体中积累，但在未保护心脏的线粒体中无染色。
异氟醚进行的麻醉后处理通过抑制糖原合酶激酶3β来防止mPTP开放，从而有效保护心脏免受再灌注损伤。
