Skip to main content
. 2018 Aug;59(2):167–178. doi: 10.1165/rcmb.2017-0361OC

Figure 1.

Figure 1.

Role of Chymotrypsin-like elastase 1 (Cela1) in postnatal lung elastin remodeling. (A) The mean linear intercepts (MLI) of Cela1−/− Postnatal Day (PND)14 lungs (alveolar stage of lung development; n = 9) were 18% smaller than wild type (WT, n = 6; Cela1+/−, n = 5), with a trend toward smaller intercepts at PND3 (saccular stage of lung development; WT, n = 8; Cela1−/−, n = 7) and 8 weeks postnatally (PN) (adult lung; WT and Cela1−/−, n = 8 per group). (B) PND14 WT lungs demonstrated the typical localization of dense elastin bands to septal tips. Scale bars: 100 μm. (C) Cela1−/− lungs had less dense septal tip elastin bands and more diffuse elastin fibers distributed throughout distal airspace walls. (D) The lung homogenates of Cela1−/− PND14 mice had less elastase activity than WT lung homogenates (n = 6 per group). (E) Western blot of PND14 lung homogenates indicated that Cela1−/− mouse lungs had approximately half the soluble tropoelastin of WT lungs. (F) Morphometric quantification of total lung elastin demonstrated a 45% reduction in lung elastin at PND14 and a 29% reduction at 8 weeks PN. To account for differences in lung density, values were normalized to tissue area, but similar findings were present when normalized to lung area. (G) As assessed using the flexiVent system, 8 weeks PN Cela1−/− mouse lungs (n = 9) were more elastic (i.e., more stiff) than WT lungs (n = 7). These differences were not age or sex dependent. KO = knockout.