Effect of aminoglycoside otic drops on isolated cochlear outer hair cells with and without liver extract activation.
OBJECTIVE
To assess the ototoxicity of commercially available Gentacidin and TobraDex ear drops with and without liver extract activation using isolated cochlear outer hair cells (OHCs).


METHODS
OHCs from adult chinchilla cochleae were exposed to standard bathing solution (SBS), liver extract alone and Gentacidin and TobraDex ear drops with and without liver extract. All experiments were performed at an osmolality of 305 +/-5 mOsm, at room temperature and for up to 60 min. OHC images were recorded using an inverted microscope and analyzed electronically. Time to cell death and changes in cell length were measured.


RESULTS
The time to cell death and the percent change in cell length were significantly shorter in the Gentacidin+liver extract group than in the Gentacidin alone group (p < 0.05). The TobraDex+liver extract group showed a significantly decreased time to cell death compared to the SBS control group (p < 0.05). There were no significant differences in cell length or time to cell death between the TobraDex+liver extract group and the TobraDex alone group (p > 0.05).


CONCLUSIONS
This study suggests that the cytotoxicity of aminoglycoside ear drops to isolated OHCs in vitro requires
Choi
Dukjoo
D
Division of Otolaryngology-Head & Neck Surgery, Loma Linda University School of Medicine and Jerry L. Pettis Veterans Medical Center, Loma Linda, CA, USA.
Park
Seong Kook
SK
Martin
Paul
P
Russell
Paul
P
Kim
Paul
P
John
Earnest O
EO
Jung
Timothy T K
TT
D000617:Aminoglycosides / Q000633:toxicity*; D000818:Animals; D000900:Anti-Bacterial Agents / Q000633:toxicity*; D016923:Cell Death / Q000187:drug effects; D048429:Cell Size / Q000187:drug effects; D002682:Chinchilla; D005839:Gentamicins / Q000633:toxicity*; D018072:Hair Cells, Auditory, Outer / Q000187:drug effects*; D066298:In Vitro Techniques; D008110:Liver Extracts / Q000494:pharmacology*; D014031:Tobramycin / Q000633:toxicity*
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D005839:Gentamicins; D008110:Liver Extracts; D014031:Tobramycin