Silica-induced model of pulmonary fibrosis.

<p>Shown is representative staining of 5 μm histological sections of lung from saline- (left panels) or silica-instilled animals (right panels) at eight weeks post-instillation. Picrosirius red staining is shown in panels A-D, scale bar = 500 μm, shown in panels A and C, applies to panels A-D. (A) Representative lung architecture in saline-instilled animals. (B) Fibrotic nodules (representative nodule indicated by arrow) are evident in the lungs of silica-instilled animals. Representative Picrosirius Red staining under polarized light shows thick (red) and thin (green/yellow) collagen fibrils in lungs of saline-instilled control animal (C) and silica-instilled animal (D). Representative fibrotic nodule indicated by arrow (D). Masson’s Trichrome staining is shown in panels E-H. Lung architecture in a representative saline-instilled (E) or silica-instilled (F) animal. Scale bar = 100 μm shown in panel E, applies to panels E-F. High magnification images (boxes in (E) and (F) indicate inset) of Masson’s Trichrome stain indicate presence of collagen fibrils (representative fibril indicated by arrow) in silica-instilled animal (H) versus saline-instilled lungs (G). Scale bar = 25 μm shown in panel H, applies to panels G-H. Representative sections with Herovici’s stain from saline- (I) and silica-instilled animals (J). Scale bar = 100 μm shown in panel I, applies to panels I-J. High magnification images (boxes in (I) and (J) indicate inset) demonstrate presence of thin (blue) and thick (red) collagen fibrils in silica-instilled (L) versus saline-instilled animals (K). Scale bar = 25 μm shown in panel L, applies to panels K-L.