Fig. 6

Immunohistochemistry from IMP co-administration study. Mice were exposed to silica or vehicle weekly for the first four weeks, while receiving IMP or PBS by osmotic pump for entire six week duration. Light photomicrographs are lung sections immunohistochemically stained for neutrophils or inflammatory mononuclear cells (red chromogen; dashed arrows) with hematoxylin counterstain from mice treated with (a) vehicle, (b) IMP, (c) silica, and (d) silica + IMP. Mice treated with vehicle- or IMP-only had no areas of pulmonary inflammation, with only a few widely scatter neutrophils in the alveolar septa. Silica treatment resulted in conspicuous aggregates of inflammatory monocytes and neutrophils that are often associated with microgranulomas or adjacent to ectopic lymphoid tissue, as well as alveolar proteinosis (asterisk). IMP reduced this silica-associated pathology to only a small solitary aggregate of inflammatory cells. Abbreviations: a = alveolar parenchyma; b = bronchiolar airway; v = blood vessel. Tissue was observed from n ≥ 3 mice per treatment condition