Surface-lining layer of airways in cystic fibrosis mice.
Lung disease is the major cause of death in individuals suffering from cystic fibrosis (CF), with abnormal lung-lining fluids occurring as early as early infancy. However, the precise etiology of CF lung disease is still poorly understood. We investigated the structural components of the airway surface-lining layer in targeted Cftrtm1HGU/Cftrtm1HGU mutant mice and non-CF controls. Five lungs per animal group were fixed by intravascular triple perfusion. The ultrastructure of the surface-lining layer of large and small intrapulmonary conducting airways was systematically investigated according to a standard protocol in transmission and scanning electron micrographs. In both animal groups, the surface-lining layer consisted of an aqueous phase and an osmiophilic film of variable thickness at the air-fluid interface. The aqueous phase usually did extend <1 microm beyond the uppermost tips of the epithelial cells in both animal groups. The aqueous phase of the small airways was slightly more electron dense in Cftrtm1HGU/Cftrtm1HGU than in non-CF mice. Neither the ultrastructure of the surfactant film at the air-fluid interface nor the forms assumed by the osmiophilic structures associated with surfactant turnover in the aqueous layer differed significantly in Cftrtm1HGU/Cftrtm1HGU and non-CF mice. Hence, there were no signs of any ultrastructural abnormalities in the surface-lining layer of young adult Cftrtm1HGU/Cftrtm1HGU mice before infection with CF-related pathogens.
Geiser
Marianne
M
Institute of Anatomy, Division of Histology, University of Bern, Bühlstr. 26, CH-3000 Bern 9, Switzerland. geiser@ana.unibe.ch
Bastian
Sara
S
D000367:Age Factors; D000818:Animals; D003550:Cystic Fibrosis / Q000473:pathology*; D051379:Mice; D018181:Mice, Inbred CFTR; D008822:Mice, Transgenic; D008854:Microscopy, Electron; D008855:Microscopy, Electron, Scanning; D011650:Pulmonary Alveoli / Q000473:pathology* / Q000648:ultrastructure; D020545:Respiratory Mucosa / Q000473:pathology* / Q000648:ultrastructure