OVA experimental asthma model. (A) Two IP sensitizing doses of OVA and 3 IT challenges were given on indicated days. Hematoxylin and eosin staining of lung sections indicates the infiltration of leukocytes and airway thickening of OVA-treated animals. DEX (5 mg/kg, intraperitoneally, 24 hours) reduced the number of leukocytes in lungs (n = 6). Scale bar, 1 mm. (B) Differential cell counts (averages ± SD) of the bronchoalveolar lavage indicated that OVA-treatment elevated the eosinophil number, a process that was blocked by DEX (n = 6; *significantly greater than CON, P < .01; 1-way ANOVA followed by Tukey posthoc test).