X-RAY-MICROANALYSIS OF NATIVE AIRWAY SURFACE LIQUID COLLECTED BY CRYOTECHNIQUE

The airway surface liquid (ASL) that lines the surface epithelium of t he tracheobronchial tree is of vital import ance to the airway defence against microbial invasion and damage due to environmental factors. L ittle is known about the ASL collected in situ! in native conditions, owing to difficulties in collecting ASL without causing damage to the airway mucosa. We have developed a method to collect and analyse the e lemental composition of tracheal ASL in pathogen-free mice. A speciall y designed cryoprobe, adapted to the internal curvature of the mouse t rachea, was used to collect the native ASL from the tracheal surface, The complete ASL elemental composition including [Na] = 5.5 +/- 0.3, [ Cl] = 1.3 +/- 0.3, [K] = 1.1 +/- 0.2, [Ca] = 1.2 +/- 0.3, [P] = 1.5 +/ - 0.8, [S] = 1.7 +/- 0.4 and [Mg] = 1.3 +/- 0.4 mmol L-1 was determine d by X-ray microanalysis. We demonstrate here that the technique that we used for ASL collection maintained perfectly the airway epithelial integrity and functionality.