Figure 1

Morphometric analysis of BREs. The thickness of the unchallenged tracheal epithelium (A) was significantly reduced at 48 (*p ≤ 0.001) and 72 (**p = 0.01) hpc when compared with T0. However, in absolute terms, such differences were extremely small and always less than 5 µm. No significant difference was observed between non-infected and challenged tracheal explants (p ≥ 0.05). The thickness of the unchallenged bronchial epithelium (B) was not significantly modified along the entire time course of the experiment. No significant difference was observed between non-infected and challenged bronchial explants (p ≥ 0.05). The surface of the unchallenged alveolar walls—expressed as percentage of the entire field of observation—was not significantly modified along the entire the time course of the experiment (C). No significant difference was observed between non-infected and challenged lung explants (p ≥ 0.05). Data were represented as the mean ± SD.