Fig. 6

µCT-guided SEM reveals nanoscale ultrastructural details of airway mucus plugs. (a) Whole-lung µCT scan of a juvenile βENaC-tg mouse, used to localise a mucus plug within an airway as a region of interest (ROI) for downstream SEM. Following ROI identification, an optimal cutting plane (green line) was selected for subsequent SEM processing. (b) Low magnification SEM image of the ROI identified in (a), showing pulmonary arteries (PA) and airways (AW), one of which is occluded by a dense mucus plug. This view illustrates the overall lung architecture and the spatial relationship between airways and surrounding parenchyma. (c) High magnification SEM image of the mucus plug from the region highlighted in (b). (d) Nanoscale image of the region shown in (c), revealing a goblet cell with clustered mucin granules (§) and buried kinocilia (*) beneath a dense mucus layer. The mucus plug displays a well-defined border and a compact structure, and its finely preserved filamentous network, illustrates the cohesive nature of mucus plugs in βENaC-tg mice. SEM parameters: Working distance 5.4–5.5 mm, SE2 detector, and accelerating voltage 2 kV. Dashed line delineates border between epithelium and mucus. Stippled line delineates a superficial mucus compartment of different texture. Scale bars: 100 μm (b), 10 μm (c), and 2 μm (d). µCT = micro-computed tomography. SEM = scanning electron microscopy. βENaC-tg = βENaC-transgenic. CC = club cells. GC = goblet cells.