[Edaravone protects hearing from acute acoustic trauma in guinea pigs].

OBJECTIVE

To assess whether the free radical scavenger, edaravone, could provide protection from oxidative stress and hearing loss induced by noise exposure.

METHODS

Forty-eight guinea pigs were divided into six groups and exposure to a stationary noise at 125 dB SPL for 2 h only once. Group A: measured hearing and reactive oxygen species (ROS) level without noise exposure. Group B: intratympanic saline injection. Group C: intratympanic edaravone injection. Group D: exposed to noise for 2 h. Group E: intravenous edaravone injection after noise exposure. Group F: intratympanic edaravone injection after noise exposure. All animals of group D, E and F were measured hearing with ABR before noise exposure, immediately after noise exposure and at 2, 6, 12, 24, 48, 72 h after noise exposure, and then were decapitated for ROS measurement with electron spin resonance technology.

RESULTS

After noise exposure, the ABR threshold of group D increased immediately after acute acoustic trauma and did not get right finally, while group F came back about 10 dB SPL. The normal level of ROS in the cochlea of guinea pigs was about 21.68 (cm/g) and significantly increased after acute acoustic trauma, reaching its peak in 2h, and didn't return to normal after 72 h. Group E did not inhibit free radicals, while group F showed significant effect on inhibiting production of free radicals.

CONCLUSIONS

The level of ROS in cochlea were decreased significantly after intratympanic edaravone injection. The mechanism may due to its effective clearance of the ROS in cochlea.