(A) L2-IL5 transgenic mice and WT littermate controls were exposed to OXA-induced esophagitis and assessed for esophageal eosinophils using MBP immunohistochemistry or immunofluorescence for Siglec-F in conjunction with Hypoxyprobe-1 (Hx-1) (n = 3–9). Eosinophils were enumerated based on MBP staining per high-power field (HPF). Primary peripheral blood human eosinophils were isolated and stimulated in the presence or absence of PMA and assessed for oxygen consumption over time (minutes) (n = 3). Scale bars: 20 μm. (B) L2-IL5 transgenic mice and WT littermate controls were exposed to OXA-induced esophagitis and assessed for tissue oxygen tension by Hypoxyprobe-1 (Hx-1) immunofluorescent staining, which was quantified to measure the area of tissue under hypoxic constraints (n = 9 per group). Scale bars: 50 μm. (C) Whole esophageal tissues from OXA-challenged L2-IL5 and WT littermate control mice were assessed for HIF-1α protein expression by Western blot and quantified by densitometry (n = 4–6). WT ODD-LUC and L2-IL5/ODD-LUC luciferase reporter mice were challenged with OXA-induced esophagitis and assessed by luciferase assay for HIF/luciferase activity relative to total tissue protein (n = 12). OXA-challenged L2-IL5 and WT littermate control mice were assessed for HIF1A and GLUT1 mRNA expression by real-time RT-PCR (n = 5). (D) OXA-challenged L2-IL5 and WT littermate control mice were assessed for histologic activity scores from H&E-stained esophageal tissues (n = 8–9). Scale bars: 50 μm (top); 20 μm (bottom). (E) Whole esophageal tissues were assessed for claudin-1 protein by Western blot and quantified by densitometry (n = 11), and were assessed for CLDN1 mRNA transcript expression by real-time RT-PCR (n = 5). Representative blot is presented. Statistical significance was assessed using Students’ t test. *P < 0.05, **P < 0.01, ***P < 0.001. Data are expressed as means ± SEM and represent a minimum of 3 experimental repeats.