Isoflurane induces a postconditioning effect on bovine pulmonary arterial endothelial cells exposed to oxygen-glucose deprivation.

Application of volatile anesthetics during the onset of reperfusion reduced ischemia-induced cardiac and brain injury (anesthetic postconditioning). This study was designed to evaluate whether volatile anesthetics induced a postconditioning effect in endothelial cells. Bovine pulmonary arterial endothelial cell (BPAEC) cultures were exposed to oxygen-glucose deprivation, a condition to simulate ischemia in vitro, for 3 h. The volatile anesthetics isoflurane and desflurane were applied during the early phase of simulated reperfusion. Cell injury was quantified by lactate dehydrogenase (LDH) release and flow cytometrical measurement after annexin V and propidium iodide staining. Oxygen-glucose deprivation and the subsequent simulated reperfusion increased LDH release and annexin V-positive staining cells, a characteristic of cell apoptosis. Posttreatment with isoflurane, but not desflurane, reduced this cell injury. This protection was apparent even when 2% isoflurane was applied at 60 min after the onset of reperfusion. The isoflurane postconditioning effect was abolished by glybenclamide, a general ATP sensitive K(+) (K(ATP)) channel blocker, 5-hydroxydecanoate, a mitochondrial K(ATP) channel blocker, and chelerythrine, a protein kinase C inhibitor. Diazoxide, a mitochondrial K(ATP) channel activator, applied at the onset of reperfusion also decreased oxygen-glucose deprivation-induced endothelial cell injury. This diazoxide-induced protection was abolished by chelerythrine and 5-hydroxydecanoate. We conclude that isoflurane induced a postconditioning effect in BPAEC. The effective time window of isoflurane postconditioning was from 0 to 60 min after the onset of reperfusion. This isoflurane postconditioning effect may be mediated by mitochondrial K(ATP) channels and PKC. PKC may be downstream of mitochondrial K(ATP) channels for this isoflurane effect.