Histology of picrosirius stained lung slices from C57BL/6 mice.

<p>Collagen (green) visualized by picrosirius staining in three slices of the left lung lobe (upper row). Magnified views (×200) of a portion of the corresponding histological slices are shown in the bottom row. A) Stained collagen content in saline treated mouse lung 37 days after administration. B) Stained collagen content in a mouse lung 37 days after last IN bleomycin administration (0.25 mg/kg on six consecutive days). C) Collagen content in a mouse lung 37 days after last OA of bleomycin (0.25 mg/kg on six consecutive days). Compared to the IN administration, the amount of picrosirius was six times higher when bleomycin was oropharyngeally aspirated and the distribution of picrosirus staining was more homogeneous.