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Effects of otic drops on chinchilla tympanic membrane
M Masaki1, C G Wright, D H Lee
1Department of Otorhinolaryngology, University of Texas Southwestern Medical Center, Dallas.
Abstract:
Experimental studies have shown that if antibiotic otic drops reach the middle ear cavity they produce severe inflammation. However, the effects of these preparations on the tympanic membrane have not been thoroughly investigated. This study was designed to assess morphological changes in the chinchilla tympanic membrane two to 21 days after a single 0.2-mL application of an antibiotic otic preparation (Cortisporin Otic Suspension) to the middle ear cavity. At two days, the epidermal and the mucosal layers were destroyed. By four days, reepithelialization had occurred and all layers of the tympanic membrane subsequently became markedly hyperplastic. Disruption of the fibrous layer, invasion of keratinizing epidermis to the medial surface, and perforation were observed at three weeks. These findings indicate that tympanic membrane damage is a potentially significant aspect of the ototoxic properties of topical otic preparations.
Insights
Topical antibiotic ear drops can cause severe tympanic membrane damage, including inflammation and perforation. This study reveals significant morphological changes in the chinchilla tympanic membrane after otic preparation application.
Area of Science:
- Otolaryngology
- Otic Preparations Research
- Tympanic Membrane Pathology
Background:
- Antibiotic otic drops reaching the middle ear cavity are known to cause severe inflammation.
- The specific effects of these preparations on the tympanic membrane require further investigation.
Purpose of the Study:
- To assess the morphological changes in the chinchilla tympanic membrane after middle ear application of an antibiotic otic preparation.
- To evaluate the ototoxic potential of topical otic preparations on tympanic membrane integrity.
Main Methods:
- A single 0.2-mL application of Cortisporin Otic Suspension was administered to the middle ear cavity of chinchillas.
- Morphological changes in the tympanic membrane were examined at two, four, and 21 days post-application.
Main Results:
- At two days, significant destruction of the epidermal and mucosal layers was observed.
- By four days, reepithelialization occurred, followed by marked hyperplasia of all tympanic membrane layers.
- At three weeks, findings included disruption of the fibrous layer, invasion of keratinizing epidermis, and perforation.
Conclusions:
- Topical otic preparations can induce significant tympanic membrane damage.
- Morphological changes observed suggest a potentially significant ototoxic effect of these preparations.
- Tympanic membrane integrity is compromised by otic preparations, highlighting the need for careful administration.