Expression of macrophage migration inhibitory factor and CD74 in the inner ear and middle ear in lipopolysaccharide-induced otitis media
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Published on: February 22, 2017
Hisashi Ishihara1, Shin Kariya1, Mitsuhiro Okano1
1a Department of Otolaryngology-Head and Neck Surgery , Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences , Okayama , Japan.
Conclusion:
Significant expression of macrophage migration inhibitory factor and its receptor (CD74) was observed in both the middle ear and inner ear in experimental otitis media in mice. Modulation of macrophage migration inhibitory factor and its signaling pathway might be useful in the management of inner ear inflammation due to otitis media.
Objectives:
Inner ear dysfunction secondary to otitis media has been reported. However, the specific mechanisms involved are not clearly understood. The aim of this study is to investigate the expression of macrophage migration inhibitory factor and CD74 in the middle ear and inner ear in lipopolysaccharide-induced otitis media.
Method:
BALB/c mice received a transtympanic injection of either lipopolysaccharide or phosphate-buffered saline (PBS). The mice were sacrificed 24 h after injection, and temporal bones were processed for polymerase chain reaction (PCR) analysis, histologic examination, and immunohistochemistry.
Results:
PCR examination revealed that the lipopolysaccharide-injected mice showed a significant up-regulation of macrophage migration inhibitory factor in both the middle ear and inner ear as compared with the PBS-injected control mice. The immunohistochemical study showed positive reactions for macrophage migration inhibitory factor and CD74 in infiltrating inflammatory cells, middle ear mucosa, and inner ear in the lipopolysaccharide-injected mice.
Insights
Macrophage migration inhibitory factor (MIF) and its receptor (CD74) are significantly expressed in experimental otitis media. Targeting MIF signaling may help manage inner ear inflammation from otitis media.
Area of Science:
- Otolaryngology
- Immunology
- Pathology
Background:
- Otitis media can cause inner ear dysfunction, but the underlying mechanisms are unclear.
- Macrophage migration inhibitory factor (MIF) and its receptor (CD74) are key inflammatory mediators.
Purpose of the Study:
- To investigate the expression of MIF and CD74 in the middle and inner ear during lipopolysaccharide-induced otitis media in mice.
Main Methods:
- Lipopolysaccharide (LPS) or phosphate-buffered saline (PBS) was injected into the middle ear of BALB/c mice.
- Temporal bones were analyzed using PCR, histology, and immunohistochemistry 24 hours post-injection.
Main Results:
- LPS-injected mice showed significantly increased MIF expression in both middle and inner ears compared to controls.
- Immunohistochemistry confirmed MIF and CD74 presence in inflammatory cells and tissues of the middle and inner ear.
Conclusions:
- Significant expression of MIF and CD74 occurs in experimental otitis media affecting both middle and inner ear.
- Modulating MIF signaling pathways could be a therapeutic strategy for inner ear inflammation associated with otitis media.
