Fig. 7
Ki67 proliferation index and genes corresponding to proliferation. Light photomicrographs, at low and high magnifications, of centriacinar regions of the lung from mice exposed by inhalation to A, B filtered air, C, D CB-O3 for one day, or E, F CB-O3 for four days. Lung tissue sections were immunohistochemically stained for Ki67 (brown chromagen in nuclei of epithelial cells undergoing DNA synthesis, solid arrows) and counterstained with hematoxylin. Stippled arrows, aggregates of carbon black particles; tb terminal bronchioles, ad alveolar ducts, e bronchiolar epithelium, a alveoli. (n = 3). G The top canonical pathway in Ingenuity Pathway Analysis (IPA) modified in co-exposure at day four (n = 3). Red indicates an increase in expression of the gene in the transcriptomic analysis. The darker the shade of red, the greater increase in expression. Day 1 (n = 4, each group) and Day 4 (n = 3, each group). Number following the exposure condition denotes number of times (either one or four) animals were exposed. Animals were euthanized and analyzed 24 h post single or four exposures. tb terminal bronchiole, ad alveolar duct, a alveolar parenchyma, e bronchiolar airway epithelium, DE differentially expressed genes