Age-related decrease in the mitochondrial sirtuin deacetylase Sirt3 expression associated with ROS accumulation in...

Area of Science:

• Neuroscience
• Auditory System Research
• Aging Studies

Background:

• Age-related hearing loss (central presbycusis) impairs speech perception and sound localization.
• Understanding its mechanisms is crucial for developing effective interventions.
• Mitochondrial dysfunction and oxidative stress are implicated in aging processes.

Purpose of the Study:

• To investigate the role of Sirt3 in the pathogenesis of age-related central auditory cortex deterioration.
• To explore the relationship between Sirt3, oxidative stress, and central presbycusis mechanisms.
• To utilize a D-galactose-induced rat model for mimetic aging studies.

Main Methods:

• Utilized a D-galactose (D-Gal) induced rat model for mimetic aging.
• Assessed malondialdehyde (MDA) levels and manganese superoxide dismutase (SOD2) activity in the auditory cortex.
• Examined mitochondrial DNA (mtDNA) deletion, ultrastructure, and apoptosis in the auditory cortex.
• Investigated Sirt3 expression and its association with SOD2 acetylation.

Main Results:

• Increased MDA levels and reduced SOD2 activity were observed in aging and D-Gal treated rats.
• Mitochondrial DNA deletion, abnormal ultrastructure, and apoptosis were present in the auditory cortex.
• Decreased Sirt3 expression correlated with increased SOD2 acetylation, reducing SOD2 activity.
• Accumulated oxidative stress resulted from diminished SOD2 activity and impaired reactive oxygen species (ROS) clearance.

Conclusions:

• Sirt3 plays a critical role in central presbycusis, potentially by regulating SOD2 activity.
• Reduced Sirt3 expression contributes to oxidative stress and auditory cortex aging.
• Targeting Sirt3 may offer a novel therapeutic strategy for aging and oxidative stress-related auditory dysfunction.