Static magnetic field affects oxidative stress in mouse cochlea

Area of Science:

• Otorhinolaryngology
• Biophysics
• Toxicology

Background:

• Oxidative stress is implicated in noise-induced hearing loss.
• Static magnetic fields (SMF) may influence oxidative processes within tissues.

Purpose of the Study:

• To investigate the impact of SMF on noise-induced changes in cochlear reactive oxygen species (ROS) and hearing thresholds.
• To determine if SMF exposure affects the biochemical markers of oxidative stress and antioxidant activity in the cochlea following noise exposure.

Main Methods:

• C57BL/6 mice were exposed to 119 dB SPL, 4 kHz octave band noise for 8 hours.
• Auditory brainstem response (ABR), lipid peroxidation (LPO) levels, superoxide dismutase (SOD) activity, and catalase activity were measured in the cochlea.
• Measurements were taken before and at five time-points over two weeks post-noise exposure, with and without SMF exposure.

Main Results:

• Noise exposure alone did not result in permanent functional hearing damage as assessed by ABR.
• Significant differences in LPO levels, catalase, and SOD activity were observed between groups exposed to noise plus SMF and noise only.
• SMF exposure in conjunction with noise led to increased ROS levels in the cochlea.

Conclusions:

• SMF exposure appears to increase cochlear ROS levels following noise exposure.
• Concurrently, SMF exposure accelerates the activation of antioxidant enzymes, suggesting a complex interaction with noise-induced oxidative stress.