Methyl thiazolyl tetrazolium and lactate dehydrogenase (LDH) release assay in cultural astrocytes exposed to oxygen–glucose deprivation (OGD). Cell viability of astrocytes was increased (A), whereas cytotoxicity was inhibited (B) by sevoflurane preconditioning (Sevo). Data are expressed as mean ± SD (n = 6). *P < 0.05 in comparison with vehicle group.