Hyperplasia of Type 2 pneumocytes following 0.34 ppm nitrogen dioxide exposure: quantitation by image analysis.
Swiss Webster male mice were exposed to intermittent 0.34 ppm nitrogen dioxide for 6 wk. Quantitative image analysis showed increased Type 2 cell numbers in each of the three lobes measured, with and without adjustment to alveolar wall measurements for lung volume normalization (e.g., P less than .037 for Type 2 cell number adjusted to alveolar wall perimeters, combined lobe analysis of variance). The exposed animals dominated the upper quartile ranking of the cell number/alveolar area ratio computations (P less than .025), which implied the presence of an especially susceptible subpopulation of animals. The Type 2 cell increase is believed to result from damage and loss of Type 1 cells, the reversibility and progression of which are presently unknown. The data also suggest an increased size of the Type 2 cell, and possibly slight atelectasis and/or edema of the alveolar walls.
D000818:Animals; D006652:Histological Techniques; D006965:Hyperplasia; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008168:Lung / Q000187:drug effects / Q000473:pathology*; D008297:Male; D051379:Mice; D009585:Nitrogen Dioxide / Q000633:toxicity*; D011650:Pulmonary Alveoli / Q000187:drug effects / Q000473:pathology
D007770:L-Lactate Dehydrogenase; D009585:Nitrogen Dioxide