Figure 6

Neratinib does not alter alveolar area or perimeter in chronic mouse models of lung disease. Fixed mouse lung tissue slices were stained with H&E (A). Alveoli were identified by a lumen surrounded by characteristically thin squamous epithelial cells and classified as intact (blue stars) or damaged (red stars) and differentiated from bronchioles (orange arrowhead) as described in the Materials and methods. Area and perimeter measurements were calculated using the outline tool (dotted lines) in NIS-Elements. Initially, random alveoli were selected for analysis; however, this resulted in the majority measured being intact (B, C). Each dot represents one alveolus, line at median; 20 alveoli measured across two lung slices per mouse, in the induction dosing study. To assess only damaged alveoli, a lower threshold of 500 μm² for area and 75 μm for perimeter was set, and alveoli below these sizes were excluded from the analysis. Median damaged alveolar area and perimeter per mouse were assessed, and no differences between treatment groups were found with either the induction dosing protocol (D, E) or the therapeutic dosing protocol (F, G). (D–G) Each dot represents one median alveolar area/perimeter per mouse, calculated from 20 alveolar measurements across two lung slices. Bars show mean ± standard deviation. Unpaired t-test was used to compare treatment groups.