Ebselen prevents noise-induced excitotoxicity and temporary threshold shift

Area of Science:

• Ototolaryngology
• Neuroscience
• Pharmacology

Background:

• Noise exposure is a significant cause of hearing loss.
• Peroxynitrite is implicated in noise-induced auditory damage.
• Temporary threshold shift (TTS) is a common consequence of noise exposure.

Purpose of the Study:

• To investigate the efficacy of ebselen, a peroxynitrite scavenger, in preventing noise-induced temporary threshold shift (TTS).
• To evaluate the protective effects of ebselen against noise-induced cellular pathology in the auditory system.

Main Methods:

• Guinea pigs were administered ebselen or a vehicle orally one hour before exposure to 115 dB SPL 4-kHz octave band noise for three hours.
• Auditory brainstem response (ABR) thresholds were measured to assess hearing function.
• Auditory nerve and inner hair cell structures were examined for pathological changes.

Main Results:

• Noise exposure caused a significant increase in ABR thresholds (25-45 dB), which resolved within seven days in control animals.
• Ebselen administration completely abolished the noise-induced ABR threshold shift.
• Noise exposure led to swelling of afferent dendrites beneath inner hair cells, a pathology significantly reduced by ebselen.

Conclusions:

• Scavenging peroxynitrite with ebselen effectively attenuates noise-induced temporary threshold shift (TTS).
• Ebselen demonstrates protective effects against noise-induced excitotoxicity and associated cellular damage.
• These findings highlight the potential of ebselen as a therapeutic agent for preventing noise-induced hearing loss.