Figure 4

Epithelial profile of TS induced squamous metaplasia in proximal airways. Antibodies against pan CK (A, B), CK13 (C, D) and p63 (E, F, G) were used to characterise the squamous metaplastia seen in proximal airways following TS exposure. All epithelial cells were positive for panCK (A, B). After 7 weeks TS exposure, there was sporadic staining in areas of squamous metaplasia (C) but after 14 weeks, TS exposed rats showed CK13-positive staining in suprabasal regions of the entire airway (D). Staining for p63 highlighted sporadic basal stem cells in FA exposed rats (E, arrow). After 14 weeks of TS exposure in larger airways, all cell nuclei in areas of squamous metaplasia (F) were stained but with a gradation of intensity from the basal cells (intense) to the suprabasal cells (weak). Staining with the isotype control antibody (G) showed no specific nuclear staining although there was weak background staining in the cytoplasm.