Dexmedetomidine preconditioning attenuates Cisplatin-induced ototoxicity in zebrafish.

Abstract

OBJECTIVES: Utilisation of high-frequency drills is known to increase noise

induced hearing loss due to increasing the damages of inner ear cells. This study

aimed to investigate whether preconditioning by using dexmedetomidine (DEX)

decreased the occurrence of ischemia in inner cells of the ear. METHODS: We

utilised a transgenic zebrafish line Brn3C, and the embryos were collected from

breeding adult zebrafish. Five-day-old larvae were cultured at the density of 50

embryos, and the larvae were classified into 4 groups: control, cisplatin group,

DEX group, and DEX+yohimbine; adrenoreceptor blocker group. The DEX group was

categorised into 3 subgroups by dosage; 0.1, 1, and 10 microM. Preconditioning

was performed for 150 minutes and then exposed to cisplatin for 6 hours. The

experiment was performed in 7 replicates for each group and the number of hair

cells in 3 parts of the neuromasts of each fish was determined. RESULTS: Hair

cell apoptosis by cisplatin was attenuated more significantly in the DEX

preconditioning group than in the control group. However, the preconditioning

effects were not blocked by yohimbine. CONCLUSION: The results of this study

suggest that hearing loss caused by vibration-induced noise could be reduced by

using DEX and may occur through other mechanisms rather than adreno-receptors.