Combined radiation- and gentamicin-induced ototoxicity.

Abstract

The aim of this project was to assess the suitability of prescribing gentamicin, a common aminoglycoside antibiotic that is known to be ototoxic, to patients undergoing radiotherapy for head and neck cancers. In clinical settings, there are cases of such patients taking gentamicin for infections. The gamma radiation used in radiotherapy is ototoxic and would by itself lead to sensori-neural hearing loss (SNHL) for some patients. The cell line used is the OC-k3 cell line derived from murine organ of Corti. Cell proliferation and viability assays were performed on cells treated with radiation and gentamicin for up to 72 hours post-treatment to determine proportion of cell death and extent of proliferation after treatment. Western blotting was done to elucidate the apoptotic pathways involved in apoptotic cell death induced by treatment with gentamicin and gamma radiation. The results clearly showed that OC-k3 cell death increased in a dose-dependent fashion with increasing amounts of gentamicin or radiation treatment alone. Synergistic ototoxic effects were observed when the cells were exposed to both gentamicin and radiation treatment. Western blotting results suggest that p53, PARP, and caspases of the mitochondrion-mediated pathway may play important roles in apoptotic cell death induced by gentamicin and radiation treatment.