Pulmonary histopathology. A diagram illustrates the locations of transverse tissue sections taken from the left lung lobe for microscopic examination (A). Light photomicrographs of representative lung sections taken at the level of the fifth axial airway (AA) generation and stained with hematoxylin and eosin (B-F). Representative light photomicrographs of a control animal (SAL-mouse; B), OVA-mouse (C) and SNP/OVA-mice with increasing SNP exposure doses (D-F) illustrating peribronchiolar and perivascular mixed inflammatory cell infiltration in OVA- and SNP/OVA-mice (arrows). Greater airway-associated inflammation is present in SNP/OVA-mice exposed to concentrations of 100 and 400 μg SNP (E and F, respectively) compared to the SAL- and OVA-mice. Scale bars = 1 mm.