An experimental model and automated methodology for the analysis of the effects of ambient levels of air pollutants on the lung

This article discusses a series of studies designed to develop and automate a method for quantitation of type II pneumocyte populations of the lung and their changes in response to 2 ppm NO₂ exposure. The validity and sensitivity of the automated approach were strongly supported by high correlations between manual and automated cell counts (r>0.8, P<10^-6) and between their respective baselines -numbers of alveoli and alveolar wall area (r=0.56, P<.002)-as well as by the automated detection of significant hypertrophy of type II cells following the NO₂ exposure (P<.025). The speed and versitility of the automated image analyzer create the capability for a comprehensive quantitation of the lungs at the cellular level, and the methodology as used could be applied immediately to the study of tissue loss and emphysema, and to the establishment of air quality standards through the measurement of cell population alterations.