In aging F344 rats, the expression levels of multiple genes related to glutathione, such as glutathione peroxidase 3, glutathione peroxidase 6, glutathione S-transferase (GST) kappa-1, and glutathione reductase, are upregulated compared with young rats, suggesting that the glutathione antioxidant system is the first barrier against oxidative damage to the cochlea and mitigating presbycusis [14]. This evidence concerns the gene GPX6 and presbycusis.