Figure 1.

Intratracheal FITC causes acute lung injury, chronic persistent inflammation, and pulmonary fibrosis. A single dose of intratracheal FITC was administered to Balb-c mice. Mice were killed at various times and the lungs were examined for histological changes. A: Acute lung injury demonstrated by alveolar wall edema, alveolar exudate, and acute inflammation 1 day after inoculation. B: Dense consolidation with a mixture of both acute and chronic inflammatory cells on day 7. Dense collections of mononuclear cells are present (arrow). C: Residual patchy bronchocentric inflammation at day 21 and increased extracellular matrix. Collections of mononuclear cells persist (arrow). D: Deparaffinized section of lung examined directly with the fluorescent microscope demonstrates persistent FITC staining in the peribronchial areas.