Figure 2.

Thoracic and skin mast cells in two different mouse models of mast cell deficiency.

The airways, alveoli, and skin of mice carrying one or two cKit^Wsh alleles (designated cKit^Wsh/Wt and cKit^Wsh/Wsh, respectively) or one Cpa3.Cre allele on a pure C57BL/6 background, and C57BL/6 littermate or Lyz2.Cre heterozygous control mice (n = 10/group) were sectioned and stained with toluidine blue. Representative microscopic images of toluidine blue-stained tissue sections (A-F), summary of data from n = 10 mice/group (G), and schematics of mast cell competence (colored mast cells) and deficiency (grey mast cell shadows) (H). A-F Arrows indicate mast cells in the submucosa of a large airway (A; inlay shows tracheal cartilage as positive control of metachromatic purple staining), in a large pulmonary vein (B), in the vagus nerve (C), in the thymus of a 6-week-old (D) and a 20-week-old (E) mouse, and in the esophageal submucosa (F) of C57BL/6 controls. a, alveoli; pv, pulmonary vein; al, airway lumen; vn, vagus nerve; ct, cellular thymus; ft, fatty thymus; el, esophagus lumen. G Airway, alveolar, and skin mast cell density of C57BL/6 control, cKit^Wsh/Wt, cKit^Wsh/Wsh, and Cpa3.Cre mice (summary of data from n = 10 mice/group). Shown are median with Tukey’s whiskers (boxes: interquartile range; bars: 50% extreme quartiles), raw data points (dots), and Kruskal–Wallis analysis of variance (ANOVA) probability (P) value. **, and ***: P< 0.01 and P< 0.001, respectively, for comparisons with C57BL/6 controls by Dunn’s post-tests. Only statistically significant differences are indicated. Note the airway mast cell competence of cKit^Wsh/Wt and cKit^Wsh/Wsh mice, and the complete mast cell deficiency of Cpa3.Cre mice. H Schematics depicting mast cells (purple) of the airways, alveoli, and skin of C57BL/6, cKit^Wsh/Wt, cKit^Wsh/Wsh, and Cpa3.Cre mice. Grey mast cell fadeouts indicate mast cell deficiency of the given anatomic compartment.