• Paula T Canas, Lionel J Velly, Christelle N Labrande, Benjamin A Guillet, Valérie Sautou-Miranda, Frédérique M Masmejean, André L Nieoullon, François M Gouin, Nicolas J Bruder, and Pascale S Pisano.
• Département d'Anesthésie Réanimation, Centre Hospitalier Universitaire Timone, Marseille, France.
• Anesthesiology. 2006 Nov 1; 105 (5): 990-8.

BackgroundThe purpose of this study was to clarify the role of glutamate and reactive oxygen species in sevoflurane-mediated neuroprotection on an in vitro model of ischemia-reoxygenation.MethodsMature mixed cerebrocortical neuronal-glial cell cultures, treated or not with increasing concentrations of sevoflurane, were exposed to 90 min combined oxygen-glucose deprivation (OGD) in an anaerobic chamber followed by reoxygenation. Cell death was quantified by lactate dehydrogenase release into the media and cell viability by reduction of 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium by mitochondrial succinate dehydrogenase. Extracellular concentrations of glutamate and glutamate uptake were assessed at the end of the ischemic injury by high-performance liquid chromatography and incorporation of L-[H]glutamate into cells, respectively. Free radical generation in cells was assessed 6 h after OGD during the reoxygenation period using 2',7'-dichlorofluorescin diacetate, which reacts with intracellular radicals to be converted to its fluorescent product, 2',7'-dichlorofluorescin, in cell cytosol.ResultsTwenty-four hours after OGD, sevoflurane, in a concentration-dependent manner, significantly reduced lactate dehydrogenase release and increased cell viability. At the end of OGD, sevoflurane was able to reduce the OGD-induced decrease in glutamate uptake. This effect was impaired in the presence of threo-3-methyl glutamate, a specific inhibitor of the glial transporter GLT1. Sevoflurane counteracted the increase in extracellular level of glutamate during OGD and the generation of reactive oxygen species during reoxygenation.ConclusionSevoflurane had a neuroprotective effect in this in vitro model of ischemia-reoxygenation. This beneficial effect may be explained, at least in part, by sevoflurane-induced antiexcitotoxic properties during OGD, probably depending on GLT1, and by sevoflurane-induced decrease of reactive oxygen species generation during reoxygenation.

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