Lung sections stained with PAS (A) and Sirius red (B),
respectively. PAS staining to identify mucin-containing cells (purple, top
panel); Sirius Red staining of lung sections depicts peri-bronchiolar and
perivascular collagen (red, bottom panel), original magnification x40; Scale bar
= 50 μm, representative photomicrographs are shown. (C)
Scoring of lung sections stained with periodic acid-Schiff. (D)
Recently synthesized total lung collagen was quantified by a biochemical
(Sircol) assay. (E) Quantitative image analysis of sub-epithelial
peri-bronchiolar collagen density determined by measuring Sirius red-stained
collagen in lung sections under polarized light; data was normalized to WT
untreated control and expressed as percent (%) increase. Data shown represent
means ± standard error mean (s.e.m.), *P < 0.05, **P <
0.01, WT compared with IRF5-/- animals by Mann-Whitney test. Box and
whisker plots represent the mean, IQR and minimum and maximum values. Data were
generated from four independent experiments; n=15–20 per
group.