Correlation between cumulative labeling indices measured in the terminal bronchioles and in the centriacinar region in the lungs of rats exposed to oxidant air pollutants

Abstract

Male Sprague-Dawley rats were exposed on 7 consecutive days for 8 h a night to 0.6 ppm ozone, 10.8 ppm NO2 or a mixture of the two gases. Cumulative labeling indices were measured in the epithelium of the terminal bronchioles and the adjacent centriacinar region. An excellent correlation in labeling indices between the two sites was found. It is concluded that the labeling index in the terminal bronchioles represents a sensitive measurement for ozone-induced lung injury.