Characterization of Gentamicin-Induced Apoptosis in a Cochlear Cell Model / 대한이비인후과학회지

ABSTRACT

BACKGROUND AND OBJECTIVES: Aminoglycoside antibiotics are ototoxic. Understanding of the molecular mechanisms underlying the drug-induced ototoxicity, however, has been hampered by limited cell availability. Recently, HEI-OC1 cells, which are of an immortalized cochlear cell line sensitive to ototoxic drugs, have been derived from the auditory sensory organ. This study was performed to confirm whether cultured HEI-OC1 cells can be used to evaluate aminoglycoside-induced ototoxicity and the effect of antioxidants against aminoglycoside-induced colchlear cell damage. MATERIALS AND METHOD: Gentamicin was administered for 3 days in the media containing HEI-OC1 cells. RESULTS: Cell viability was decreased by gentamicin in a dose-dependent manner. The cell number was decreased by 50% 3 days after the exposure to 2 mM gentamicin. Penicillin did not have any significant effect. Flow cytometric analysis revealed that sub G1 arrest representing cellular apoptosis was accelerated by gentamicin treatment but not by penicillin. Expression of p27Kip1, the cyclin-dependent kinase inhibitor, was exclusively increased by gentamicin. Reactive oxygen species were also increased by gentamicin when compared with those of the control or when penicillin was used. Caspase-3 activity became increased according to the elevation of gentamicin concentrations. N-acetyl cysteine, but not vitamin E or vitamin C, ameliorated cell survival dose-dependently against gentamicin. CONCLUSION:The present study reveals that the HEI-OC1 cell line is a good model to evaluate gentamicin-induced ototoxicity. The results suggest that gentamicin-induced apoptosis may be, at least partially, linked to the overproduction of a reactive oxygen species called. Nacetyl cysteine, a free radical scavenger, that decreases the gentamicin ototoxicity.