Changes in Mucosal Goblet Cell Density in Acute Otitis Media Caused by Non-typeable Haemophilus influenzae

Abstract

The correlation between secretory otitis media and increased goblet cell density in the middle ear mucosa is well established. Previous studies have shown that a single episode of acute otitis media caused by Streptococcus pneumoniaeis followed by increased goblet cell density for a period of at least 6 months, conceivably predisposing a subsequent development of secretory otitis media. In this study, 25 rat middle ears were inoculated with non-typeable Haemophilus influenzae in order to determine the effect on mucosal goblet cell density. Five rats were killed on days 4, 8, 16, 60 and 180 postinoculation, followed by dissection, staining and whole-mount embedding of the middle ear mucosae. The goblet cell density was determined in 24 well-defined localities. Compared with 25 normal middle ears, the goblet cell density was significantly increased in almost all localities, at all days on which the animals were killed. Thus, increased goblet cell density and enlargement of mucosal areas containing goblet cells persisted 6 months after the acute incident. The induced increase of goblet cell density was higher than the increase following inoculation of S. pneumoniae. We conclude that acute otitis media caused by non-typeable H. influenzae is followed by a longstanding increase in mucosal secretory capacity, likely to predispose a subsequent development of secretory otitis media.