title: Intraphagolysosomal pH in canine and rat alveolar macrophages: flow cytometric measurements.
abstract: Intracellular dissolution of inhaled inorganic particles is an important clearance mechanism of the lung and occurs in phagolysosomal vacuoles of phagocytes. Flow cytometric measurements of intraphagolysosomal pH in alveolar macrophages (AM) obtained from beagle dogs, Wistar rats, and from a baboon were made using fluorescein isothiocyanate-labeled amorphous silica particles (FSP). AM were obtained by bronchoalveolar lavage. FSP were phagocytized by AM in cell suspensions incubated in full media for 24 hr up to 6 days. Dual laser flow cytometry was performed and six-parameter list mode data were recorded from forward scatter, side scatter, and fluorescence intensities at 530 nm excited at 457 nm and 488 nm as well as logarithmic fluorescence intensity at wavelengths 630 nm excited at 488 nm. In this way it was possible to discriminate viable AM with phagocytized FSP from lysing AM with phagocytized FSP and from cells without FSP and from free FSP. Viable cells were distinguished from lysing cells by staining with propidium iodide immediately before the flow cytometric measurement. A calibration curve for the pH value was determined from FSP suspended in buffered media at pH values ranging from 3.5 to 7.5. First flow cytometrical results indicated that after an incubation time of 24 hr, the mean intraphagolysosomal pH of viable AM was 4.7 +/- 0.3 for dogs and 5.1 +/- 0.5 for rats. The intraphagolysosomal pH of the baboon AM was 4.5.
authors.affiliation: Projekt Inhalation, Gesellschaft für Strahlen- und Umweltforschung mbH München, Neuherberg, Federal Republic of Germany.
authors.forename: P
authors.initials: P
authors.lastname: Heilmann
authors.forename: W
authors.initials: W
authors.lastname: Beisker
authors.forename: U
authors.initials: U
authors.lastname: Miaskowski
authors.forename: P
authors.initials: P
authors.lastname: Camner
authors.forename: W G
authors.initials: WG
authors.lastname: Kreyling
mesh_terms: D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000166:cytology; D004285:Dogs; D005260:Female; D005434:Flow Cytometry; D006863:Hydrogen-Ion Concentration; D007958:Leukocyte Count; D008247:Lysosomes / Q000737:chemistry*; D016676:Macrophages, Alveolar / Q000737:chemistry* / Q000166:cytology / Q000648:ultrastructure; D008297:Male; D010215:Papio; D051381:Rats; D017208:Rats, Wistar; D013045:Species Specificity