Figure 4. Mechanism of suppression by isoflurane against EPO upregulation under hypoxic conditions.

(A) Expression analysis of hypoxia-inducible factor (HIF)-1α, HIF-2α, and aryl hydrocarbon receptor nuclear translocator (ARNT, also termed as HIF-1β) in the whole brain by immunoblotting. 6-week-old BALB/c mice were exposed to air (control), 10% O₂ (hypoxia) or 10% O₂ with 0.5% isoflurane (hypoxia+iso) for 3 hours. Figures are representative of at least three independent experiments. (B) Immunohistochemical staining for HIF-1α and HIF-2α in the frontal cortex of 6-week-old BALB/c mice. Mice were exposed to air (control), 10% O₂ (hypoxia) or 10% O₂ with 0.5% isoflurane (hypoxia+iso) for 3 hours. Figures are representative of 6 slices of 3 mice. Scale bars: 100 µm.