Increased upper airway resistance without airway remodeling in Ttll1−/− mice.

(A) Lung sections stained with periodic acid-Schiff (PAS) and elastic van Gieson's (EVG) stains. There were no apparent differences between the wild-type (WT) and Ttll1−/− mice (n = 4 per group). Scale bar, 200 μm. (B) Measurement of smooth muscle area. To adjust airway size, the area of the smooth muscle layer was divided by the length of the basement membrane (bars indicate mean values, n = 4 per group, two-tailed Student's t test; NS = not significant). (C) Measurements of hydroxyproline in lung homogenates. Right lower lung homogenates used for the hydroxyproline assay (bars indicate mean values, n = 4 per group, two-tailed Student's t test) (D). The baseline enhanced pause (Penh) indices of mice (bars indicate mean values, n = 10 mice per group, * P Ttll1−/− mice compared with that in the WT mice (mean ± SEM, n = 4 mice per group, † P