Goblet cell density in acute otitis media caused by Moraxella catarrhalis

Hypothesis and Background: Secretory otitis media is associated with a high ly increased goblet cell density, confirming the secretory pathogenesis of this disease. Previous studies have shown that the middle ear goblet cell d ensity, and thus the secretory capacity, are massively increased during exp erimental acute otitis media and at least 6 months thereafter, conceiv ably predisposing to the subsequent development of secretory otitis media. Thes e studies used middle ear inoculation of either Streptococcus pneumoniae, n ontypeable Haemophilus influenzae, or H. influenzae type b. The present stu dy aimed at determining the goblet cell density during and after acute otit is media caused by Moraxella catarrhalis to clarify whether this bacterium induces an equivalently enhanced secretory capacity. Methods: Twenty-five 25 rat middle ears were inoculated with M. catarrhalis . Five rats were killed on days 4, 8, 16, 60, and 180 after inoculation, fo llowed by staining, dissection, and whole-mount embedding of the middle ear mucosae. The goblet cell density was determined by counting in 24 fields, covering the entire middle ear. Results: in comparison with 15 normal middle ears, the goblet cell density was significantly increased in almost all counting localities, from day 4 a nd less than or equal to2 months after inoculation. The goblet cell density peaked on day 16, subsided thereafter, and in some areas reached a normal level 6 months after the acute incident. Mucosal areas containing goblet ce lls were consistently enlarged, thus leaving the middle ear with an increas ed secretory capacity during and 6 months after inoculation. Conclusion: The goblet cell density of the middle ear mucosa is increased d uring acute otitis media caused by M. catarrhalis and up to several months thereafter. This may predispose to the subsequent development of secretory otitis media. However, in comparison with acute otitis media caused by othe r bacteria, M. catarrhalis induced only modest changes in goblet cell densi ty.