Age-related dysfunction of the central auditory system, also known as central
presbycusis, can affect speech perception and sound localization. Understanding the pathogenesis of central
presbycusis will help to develop novel approaches to prevent or treat this disease. In this study, the mechanisms of central
presbycusis were investigated using a mimetic aging rat model induced by chronic injection of
D-galactose (D-Gal). We showed that
malondialdehyde (MDA) levels were increased and
manganese superoxide dismutase (SOD2) activity was reduced in the auditory cortex in natural aging and D-Gal-induced mimetic aging rats. Furthermore,
mitochondrial DNA (
mtDNA) 4834 bp deletion, abnormal ultrastructure and cell apoptosis in the auditory cortex were also found in natural aging and D-Gal mimetic aging rats.
Sirt3, a mitochondrial
NAD+-dependent deacetylase, has been shown to play a crucial role in controlling cellular
reactive oxygen species (ROS) homeostasis. However, the role of
Sirt3 in the pathogenesis of age-related central auditory cortex deterioration is still unclear. Here, we showed that decreased
Sirt3 expression might be associated with increased SOD2 acetylation, which negatively regulates SOD2 activity. Oxidative stress accumulation was likely the result of low SOD2 activity and a decline in ROS clearance. Our findings indicate that
Sirt3 might play an essential role, via the mediation of SOD2, in central
presbycusis and that manipulation of
Sirt3 expression might provide a new approach to combat aging and oxidative stress-related diseases.