Lung Adenocarcinoma Originates from Retrovirus Infection of Proliferating Type 2 Pneumocytes during Pulmonary Post-Natal Development or Tissue Repair
Figure 4
Mild lung injury model in adult sheep.
(A–B) Histology of lung sections of sheep treated with 3 methylindole (3MI) (A) and mock-treated controls (B). Treatment with 3MI is characterized by edema and haemorrhagic areas. (C–D) Representative images of lung sections from adult sheep treated with 3MI (C) or mock control (D) analyzed by confocal microscopy using antibodies towards CC10 (showed in green) and Ki67 (showed in red) and the appropriate fluorescent conjugates as described in Materials and Methods. Nuclei were stained with DAPI and are shown in blue. Note in panel C the extensive injury of bronchiolar epithelium (absence of CC10 staining) and proliferation of toxicant resistant Clara cell progenitors (indicated by arrows). Note in both panels C and D the terminal bronchioli (Tb). (E–F) Representative images of lung sections from adult sheep treated with 3MI (E) or mock-treated (F) analyzed by confocal microscopy using antibodies towards SP-C (showed in red) and Ki67 (showed in green). Note in panel E the presence of several SP-C+/Ki67+ cells. Nuclei were stained with DAPI and are shown in blue. Arrows indicate SP-C+/Ki67+ cells. (G) Graph representing the quantification of the data analysed by confocal microscopy. Results shown are the average numbers of SP-C+/KI-67+ (± SD) per section for both groups of animals. (H) Analysis of proliferating Clara cells was performed by counting the number of CC10/Ki67 double-positive cells in 100 terminal bronchioli per each animal. Results shown are the average numbers of CC-10+/Ki67+ (± SD) per 100 terminal bronchioli for both groups of animals. Scale bars, A–B = 200 µm; E–F = 47 µm; C–D = 89 µm.