Reduced airway remodeling in mice deficient in STAT6 and IL-4Rα. RAG2-/-, STAT6xRAG2-/- or IL-4RαxRAG2-/- mice were subjected to the asthma protocol described in Figure 3. (A) Paraffin embedded lung sections from each group of mice were stained with Masson's Trichrome. Keratin and muscle fibers are stained in red, collagen in blue, cytoplasm in light red/pink and nuclei in black. Photomicrographs of collagen deposition around the airways (panels a-c) or blood vessels (panels d-f) were collected at 10× (panels a-f) and 100× (inset) magnification. Photomicrographs (100×) of the airway smooth muscle (ASM) layer in H&E stained lung sections from each mouse group is shown in panels g-i. Arrows depict the thickness of the ASM layer (transverse section). (B) The amount of collagen present in the lung was quantified using NIH Image J software. Data is represented as area of collagen (blue stain) ± SEM. # p < 0.001. n = 20 airways/blood vessels per group. (C) The distance between the innermost aspect and outermost aspect of the smooth muscle was measured at 3 different positions around each airway, using NIH Image J software. Data is represented as airway smooth muscle thickness in μm ± SEM. * p < 0.01. An average of 30 airways was used for each group.