Fig. 1. Protective effects of isoflurane and aminoguanidine (AG) on cell viability. ( A ) Time window of delayed isoflurane treatment. The mouse C8-B4 microglial cells were incubated with 10 ng/ml lipopolysaccharide (LPS) and 10 U/ml interferon γ (IFNγ) for 24 h. Cells were exposed to 2% isoflurane for 1 h at 0, 2, 4, 8, 16, and 23 h after the initiation of the lipopolysaccharide and IFNγ stimulation. Cell viability was measured using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Results are mean ± SD (n = 10–15). * P < 0.05 compared to control. ˆ P < 0.05 compared to lipopolysaccharide plus IFNγ only. Iso-post = 2% isoflurane posttreatment. ( B ) Dose-response of isoflurane effects on cell viability. The mouse C8-B4 microglial cells were incubated with 10 ng/ml lipopolysaccharide and 10 U/ml IFNγ for 24 h. Cells were exposed to 1, 2, or 3% isoflurane for 1 h immediately after the initiation of the lipopolysaccharide and IFNγ stimulation. Results are mean ± SD (n = 8). * P < 0.05 compared to control. ˆ P < 0.05 compared to lipopolysaccharide plus IFNγ only. ( C ) AG effect. The mouse C8-B4 microglial cells were incubated with or without 10 ng/ml lipopolysaccharide and 10 U/ml IFNγ in the presence or absence of 10 μm AG for 24 h. Results are mean ± SD (n = 9). * P < 0.05 compared to control. ˆ P < 0.05 compared to lipopolysaccharide plus IFNγ only.