Impaired lung mechanics and airspace enlargement in the absence of Arhgef1. A: Quasi-static pressure-volume loops performed on wild-type (open boxes, dotted lines) and Arhgef1−/− mice (solid boxes, solid lines) from 1.5 weeks to 12 months of age. Data represent mean ± SE C57BL/6 mice n = 4, 4, 11, 4, and 6; Arhgef1−/−n = 4, 4, 12, 4, and 8 for 1.5 weeks, 3 weeks, 3 months, 6 months, and 1 year of age, respectively.B: Representative H&E stained sections of lung from C57BL/6 (left column) and Arhgef1−/− (right column) mice from 1 day old to 1 year of age. C: Mean linear intercept (μm) of alveolar septae as measured on H & E–stained wild-type (open bars) and mutant (solid bars) inflated lungs. Data represent mean ± SE For C57BL/6 mice n = 4, 4, 7, 7, 7, and 9 for Arhgef1−/− mice n = 3, 4, 7, 9, 7, and 18 for 1 day, 1.5 weeks, 3 weeks, 3 months, 6 months, and 1 year of age, respectively. *P < 0.05 for Student two-tailed t test compared with C57BL/6 mice.