Techniques for the Determination of Particle Deposition in Lungs of Hamsters

ABSTRACT

This study describes a new technical set-up for particle inhalation in hamsters as well as a modified technique for the subsequent fixation of their lungs which provide a basis for a structural analysis of particle deposition and retention. For the first time an attempt has been undertaken to determine particle deposition in anatomical compartments of the lungs. Aerosols of polystyrene particles with nominal particle diameters of either 1, 3 or 6 μm were inhaled by three deeply anesthetized hamsters breathing spontaneously through an intratracheal cannula for periods up to 30 minutes. Light scattering aerosol photometry and pneumotachography were applied to monitor for each breath respired volume, breathing cycle period and particle number in inspired and expired air. Tidal volume varied between 0.50 ± 0.03 and 0.72 ± 0.02 c^m among the three hamsters, breathing frequency between 34.4 ± 2.8 and 54.7 ± 8.0 min⁻¹. Deposition fraction per breath was 0.09 ± 0.02 for 1 μm particles, 0.24 ± 0.08 for 3 μm particles and 0 63 ± 0.03 for 6 μm particles. Immediately after inhalation, the luugs were triple fixed at 60% TLC in situ by intravascular perfusion with 2.5% glutaraldehyde, 1% osmium tetroxide and 0.5% uranyl acetate. After fixation the tissue was processed for light and electron microscopy. Enough particles have been deposited in the lungs for a subsequent assessment of particle distribution.