Jewett BS, Prazma JP, Hunter SE, Rose AS, Clark JM, Sartor BR, Pillsbury HC. Systemic reactivation of otitis media with effusion in a rat model.
Otolaryngol Head Neck Surg 1999;
121:7-12. [PMID:
10388868 DOI:
10.1016/s0194-5998(99)70114-2]
[Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
OBJECTIVE
This study addresses the interaction of bacterial antigens, specifically peptidoglycan-polysaccharide (PG-PS) and lipopolysaccharide (LPS), in the induction and reactivation of mucoid middle ear effusions.
METHODS
Twenty-seven rats underwent eustachian tube obstruction before inoculation of the middle ear bulla with PG-PS. Three weeks later, after resolution of all middle ear effusions, 6 rats were randomly selected and euthanized as the first control group (control I). The remaining 21 animals were randomly assigned to 3 groups that received intravenous injections of Krebs Ringer (control II), PG-PS, and LPS, respectively. These rats were euthanized 2 days after intravenous injection. Middle ear mucin production and histologic changes were measured in all animals.
RESULTS
The mean concentrations of mucin were 0.94 +/- 0.52 mg/mL, 0.41 +/- 0.87 mg/mL, 16.33 +/- 3.67 mg/mL, and 1.15 +/- 0.41 mg/mL in the control I, control II, PG-PS, and LPS groups, respectively. Thus the mean concentration of mucin in the middle ear lavage samples was significantly greater in rats that were injected intravenously with PG-PS than in rats in other groups (P < 0.05). Histologic analyses demonstrated a greater degree of goblet cell hyperplasia in the PG-PS group than in other groups.
CONCLUSIONS
This is the first animal model of recurring otitis media with effusion in which a systemic injection of PG-PS was used to reactivate a middle ear effusion in rats previously primed with a transtympanic injection of PG-PS. This study suggests that after otitis media with effusion has resolved, it may be reactivated by the presence of bacterial antigens and/or cytokines in the systemic circulation.
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