a) In tissue sections, CF tracheas had smaller caliber with anterior cartilage defects (arrows). HE stain, bars = 420μm, 840μm, and 1mm, respectively. b) Tracheal caliber was reduced in CF pigs as early as d54/60, (*P<0.01, Mann Whitney test). c) The trachealis muscle of non-CF and CF tracheas had similar amount of growth from d54 to d82, (NS, Mann Whitney test). d) The trachealis muscle (asterisks) had lesions, i.e. morphological evidence of smooth muscle bundles (arrows) in cross sections as early as d60 in CF pigs. HE stain, bars = 62 and 20μm, respectively. e) Submucosal glands were first detected as early as d82 in tracheas and at this time were composed of budding ducts (arrows) in both groups, HE stain, bar = 40μm. f) Submucosal glands had similar early growth in CF and non-CF at d82 (P=0.173, Mann Whitney test). Graph lines = mean.