Ovine tracheal epithelial cells differentiate optimally at sub-ambient oxygen tension.

<p>Ovine tracheal epithelial cells were cultured in an atmosphere of 7, 14 or 21% O₂. (A) Immunofluorescent staining with anti-β-tubulin (green), rhodamine-phalloidin (red) and DAPI (blue). (B) Scanning electron microscopy. (C) Immunofluorescent staining with anti-ZO-1 (green) and DAPI (blue). (D) Haematoxylin and eosin-stained histological sections. (E) Quantitation of ciliation as percentage of total area from β-tubulin staining. (F) Trans-epithelial electrical resistance measurements. Data shown are from a single representative animal with mean +/- standard deviation from three inserts displayed. (G) Quantitation of ciliation by counting ciliated cells in H&E-stained sections. (E, G) Five images from each of three inserts were analysed and data displayed is mean +/- standard deviation from four animals. Statistical significance was assessed by Student’s <i>t</i>-test (E and G) or one-way ANOVA with Dunnet’s post-test (F). Significance values are indicated by one (<i>P</i><0.05), two (<i>P</i><0.01) or three (<i>P</i><0.001) asterisks.