Automated analysis and separation of cells from the respiratory tract: preliminary characterization studies in hamsters

This paper summarizes results of preliminary experiments designed to develop automated flow-analysis methods for discerning damage to respiratory tract cells in humans exposed by inhalation of physical and chemical toxic agents, the specific goal being the determination of early atypical changes in exposed lung epithelium using the Syrian hamster as a model. Hamster respiratory cell samples obtained by lavaging the lungs with normal saline were composed of macrophages, leukocytes, ciliated columnar and basal undifferentiated cells. Samples were stained with fluorescent dyes specific for different biochemical parameters and analyzed in liquid suspension as they flowed through a chamber intersecting a laser beam of exciting light. Multiple sensors measured the fluorescence and light-scatter optical signals on a cell-by-cell basis. Cellular parameters proportional to optical measurements (e.g., cell size, deoxyribonucleic acid content, protein, esterase activity, nuclear and cytoplasmic diameter) were displayed as frequency distribution histograms. Cells were also separated according to various cytologic parameters and identified microscopically. The basis operating features of the methodology are presented, along with representative examples of results which illustrate the initial characterization of normal exfoliated respiratory tract cells. As the technology is adapted further to the analysis of these cell types, measurement of changes in cellular properties as a function of toxic exposure will be performed.