Lung tracheal epithelium is altered in Sox9 knockout mice. (A-B) Hematoxylin and eosin (H&E) staining of embryonic day (E) 18.5 tracheal sections, showing altered morphology of epithelial cells in (B) the mutant trachea compared with (A) the wild-type (A′ and B′ are high magnification inserts of A and B respectively). (C, D) Intralobar sections of main bronchi stained with H&E. No obvious differences are seen between (C) the wild-type and (D) mutant intralobar bronchia. (E, F) Transverse sections of (E) wild-type and (F) mutant mouse tracheas stained with Alcian blue. Mutant tracheas are collapsed because of the lack of structural support normally given by the cartilage rings. (G) Electron microscopy of epithelial cells lining the mutant tracheal revealed the presence of Clara cells. (H) Real time RT-qPCR analysis at E18.5 altered expression of Sftpc, Sftpa, and CC-10 genes. *P < 0.05, **P < 0.01. Values are mean ± SD.
Turcatel et al. BMC Biology 2013 11:117 doi:10.1186/1741-7007-11-117