Methionine Sulfoxide Reductase A Knockout Mice Show Progressive Hearing Loss and Sensitivity to Acoustic Trauma

Area of Science:

• Otoacoustic emissions
• Neuroscience
• Molecular biology

Background:

• Methionine sulfoxide reductases (MsrA and MsrB) are crucial for protein protection against oxidative damage.
• These enzymes play a role in mitigating the pathological effects of neurodegenerative diseases.
• Understanding MsrA's function in the auditory system is important for hearing health.

Purpose of the Study:

• To investigate the auditory phenotype of MsrA knockout mice.
• To determine the role of MsrA in protecting the cochlea from acoustic damage and noise exposure.
• To explore the expression patterns of MsrA and MsrB in the cochlea.

Main Methods:

• Characterization of auditory brainstem response (ABR) and distortion product otoacoustic emissions (DPOAE) in MsrA knockout and wild-type mice.
• Assessment of noise sensitivity at different ages.
• Quantitative analysis of MsrA and MsrB1 mRNA expression in cochlear tissues following acoustic stimulation.

Main Results:

• MsrA knockout mice displayed elevated high-frequency hearing thresholds and reduced DPOAE levels compared to controls.
• Hearing deficits progressively worsened with age in MsrA knockout mice.
• Increased MsrA mRNA levels were observed in the cochlea after acoustic stimulation, and MsrB1 mRNA expression was reduced in older MsrA knockout mice.

Conclusions:

• MsrA is identified as a protective factor in the cochlea against early-onset hearing loss and acoustic trauma.
• MsrA plays a role in mitigating noise-induced cochlear damage.
• Further research into Msr-based therapies could offer strategies for preventing noise exposure-related hearing damage.