Coenzyme Q addition to an n-6 PUFA-rich diet resembles benefits on age-related mitochondrial DNA deletion and oxidative stress of a MUFA-rich diet in rat heart

Age-related changes in cardiomyocytes reduce the capacity to recover from acute injury or to adapt during chronic disease in advanced age. N-6 polyunsaturated fatty acids (n-6PUFA) lead to higher lipid peroxidation during aging than the less oxidizable monounsaturated fatty acids (MUFA); and coenzyme Q (CoQ)-supplemented n-6PUFA lengthens the lifespan and reduces peroxidation in comparison to non-supplemented n-6PUFA. Here, lifelong feeding on MUFA, n-6PUFA, and n-6 PUFA + CoQ was compared regarding age-related alterations in rat heart. Less mitochondrial area and perimeter were reported for aged n-6 PUFA-fed animals while MUFA led to a higher density of mitochondrial cristae. Mitochondrial complexes and cytochrome c oxidase activity decreased with aging (except complex I and cytochrome c oxidase in n-6 PUFA + CoQ), while increased apoptosis-inducing factor was found with aging. MUFA led to lower mitochondrial DNA-deletion frequency. The lowest hydroperoxide levels for aged animals were found for n-6 PUFA + CoQ, which also showed lower concentrations than did n-6 PUFA. For protein oxidation, specific carbonyl compounds were lower in aged animals; meanwhile lipoxidation-derived protein-oxidation markers were higher. The results suggest that MUFA can protect mitochondria from age-related changes, and that CoQ supplementation to n-6 PUFA partially resembles MUFA benefits. Moreover, under our experimental conditions, lipid-derived oxidative damage appears to be more important than the pure protein-derived oxidative damage during aging.