Figure 2.

Small airway fibrosis develops over 18 months of age in unchallenged Cc16 ^−/− mice but not in unchallenged WT mice. Deposition of extracellular matrix (ECM) proteins around small airways having a diameter of 300–699 microns was measured on Masson's Trichrome‐stained sections of lungs from unchallenged Cc16 ^−/− versus WT mice at 6, 12, or 18 months of age. (A) Images of lung sections from mice that are representative of 5–9 mice/group at each time point. (B) Images of both lung fields containing all small airways having a diameter of 300–699 μm in each mouse (10–20 airways per mouse) were acquired using a microscope interfaced with a digital camera a camera. The thickness of the ECM protein layer deposited around the small airways measured at 12 equally spaced points around each airway using MetaMorph software. The boxes in the box‐plots show the median values and 25th and 75th percentiles for the thickness of the ECM layer, and the whiskers show the 10th and 90th percentiles (5–9 mice/group). Data were analyzed using a one‐way ANOVA and pair‐wise testing was performed using Mann–Whitney U tests. Asterisk indicates P < 0.05 compared with mice belonging to the same genotype at 6 months of age, or the group indicated.