Figure 5.

Auditory tube gating function is compromised in the absence of submucosal glands. (A) Coronal section of the rostral nose in a Junbo mouse has normal air filled nasal passages; note vomeronasal organ (vno). (B–D) Dorsal plane sections. (B) The opening of the auditory tube (at) into the nasopharynx (nd) in a Junbo mouse shows the normal mucosa of the nasopharynx is lined by ciliated epithelium (ce). (C,D) Nasopharynx (nd), auditory tubes (at) and bullae (b). (C) An auditory tube in a 45-week-old Junbo mouse with a slender profile and empty lumen; note submucosal glands (smg). (D) The auditory tube of a 13-week-old Eda^Ta mouse contains exudate (ex) and hair shaft foreign body material (fb) (inset shows higher magnification of the tube contents). (E) Auditory tube lumen area is significantly greater in Eda^Ta (n = 6 mice, 13-weeks-old) than in Edar^dlJ/dlJ(n = 6 mice, 16-weeks-old), Edar^dlJ/+(n = 6 mice, 15-16 weeks-old) and Junbo (n = 5 mice, 24–45 weeks-old). Total area for each auditory tube was measured in 50 µm step sections, and data are represented as points with the average as a bar; one-way ANOVA and Tukey’s multiple comparison test; **** P < 0.0001. (F) Bulla foreign body particle size in Edar^dlJ/dlJ and Eda^Ta mice is significantly larger than in Junbo mice. Particle sizes were measured in the bullae of Edar^dlJ/dlJ (n = 11 mice, 7-17 weeks old), Eda^Ta (n = 10, 13–30-weeks old) and Junbo (n = 9, 14–45-weeks old) mice. The graph represents data points and the median as a bar; 2-tailed Kruskal Wallis test; ****P < 0.0001 and NS not significant in Dunn’s multiple comparison test. Scale bars: 250 µm (A,B); 500 µm (C,D); 100 µm (panel D inset).