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Minocycline attenuates gentamicin induced hair cell loss in neonatal cochlear cultures
Elisa Corbacella1, Irene Lanzoni, Dalian Ding
1Department of Audiology, University of Ferrara, 44100 Ferrara, Italy.
Abstract:
Minocycline, a second-generation tetracycline antibiotic used against gram-negative and gram-positive bacteria, protects against a wide range of neurodegenerative disorders by inhibiting caspases, iNOS and the release of cytochrome c. Since aminoglycoside antibiotics damage sensory hair cells in the inner ear by activating caspase-mediated cell death pathways, we hypothesized that minocycline would protect against gentamicin (GM) ototoxicity. To test this hypothesis, postnatal day 3 (P3) rat, cochlear organotypic cultures were treated with GM alone or in combination with minocycline (10-500 microM). Treatment with GM induced a dose-dependent loss of outer hair cells (OHC) and inner hair cells (IHC). Addition of minocycline to the GM-treated cultures greatly reduced the amount of GM-induced hair cell damage in P3 cochlear cultures. The greatest protection was achieved with 100 microM of minocycline. Application of minocycline alone had no adverse effects on hair cell survival. The advantage of this combination therapy is that minocycline prevents GM-induced hair cell loss while helping to suppress the bacterial infection.
Insights
Minocycline protects against gentamicin-induced ototoxicity by preventing hair cell death in the inner ear. This combination therapy offers a potential strategy for reducing antibiotic-related hearing damage.
Area of Science:
- Neuroscience
- Pharmacology
- Ototoxicology
Background:
- Minocycline, a tetracycline antibiotic, exhibits neuroprotective properties by inhibiting cell death pathways.
- Aminoglycoside antibiotics, like gentamicin, can cause ototoxicity by damaging inner ear sensory hair cells via caspase-mediated apoptosis.
- This suggests a potential therapeutic role for minocycline in mitigating aminoglycoside-induced ototoxicity.
Purpose of the Study:
- To investigate the protective effects of minocycline against gentamicin-induced ototoxicity in a rat cochlear culture model.
- To determine the efficacy of minocycline in preventing hair cell loss caused by gentamicin exposure.
Main Methods:
- Postnatal day 3 (P3) rat cochlear organotypic cultures were utilized.
- Cultures were treated with gentamicin (GM) alone or in combination with varying concentrations of minocycline (10-500 microM).
- Hair cell damage (outer hair cells - OHC and inner hair cells - IHC) was assessed following treatment.
Main Results:
- Gentamicin exposure induced a dose-dependent loss of both OHC and IHC.
- Co-administration of minocycline significantly reduced gentamicin-induced hair cell damage.
- Optimal protection was observed with 100 microM minocycline, with no adverse effects on hair cells when applied alone.
Conclusions:
- Minocycline effectively protects inner ear sensory hair cells from gentamicin-induced ototoxicity.
- The combination of minocycline and gentamicin presents a promising therapeutic approach to prevent antibiotic-associated hearing loss.
- Minocycline's dual action of preventing ototoxicity and suppressing bacterial infection enhances its therapeutic potential.
