RT Journal Article
SR Electronic
T1 Efficiency of airway macrophage recovery by bronchoalveolar lavage in hamsters: a stereological approach
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP 1712
OP 1718
DO 10.1183/09031936.95.08101712
VO 8
IS 10
A1 M Geiser
A1 AL Serra
A1 LM Cruz-Orive
A1 M Baumann
A1 V Im Hof
A1 P Gehr
YR 1995
UL http://erj.ersjournals.com/content/8/10/1712.abstract
AB Macrophages play a central role in the defence of the respiratory tract against deposited particles. In addition to the well-studied alveolar macrophages, airway macrophages have been recognized as an important clearance factor. Bronchoalveolar lavage (BAL) has been used for functional and morphological investigations of macrophages in vitro, assuming that all macrophages are removed with equal probability from the lung surface. Airway macrophages have been found in close contact with the epithelial cells. These macrophages may not be easily removed by lavage, and they might constitute a functionally different macrophage population. We have tested the hypothesis that there exists a population of macrophages in the conducting airways that resists removal by lavage. We lavaged the lungs of four hamsters and fixed the lungs, thereafter, by intravascular perfusion. The number of macrophages in the intrapulmonary conducting airways was estimated with an unbiased stereological technique, the fractionator, and compared to the number of macrophages in the airways of four hamsters whose lungs had not been lavaged prior to fixation. This in situ study revealed that, in hamster lungs, 42% of the airway macrophages were not removed by BAL and that about 5% of all macrophages in the BAL fluid were airway macrophages. Additionally, ultrastructural alterations of the airway epithelium were found. It is concluded that there exists a population of airway macrophages that resists lavage. This is an aspect which has to be considered in studies performed with macrophages obtained by BAL, since they could represent a functionally different macrophage population.