Age-dependent accumulation of mitochondrial DNA deletions in the aortic root of atherosclerosis-prone apolipoprotein E-knockout mice

•mtDNA deletions accumulated significantly in mice as young as 2-month old.•Plaques were not detected until mice were 6-month old.•mtDNA-encoded COX III was markedly down-regulated in 2 and 16-month-old ApoE−/− mice.•The level of OGG1 protein decreased in an age-dependent manner in ApoE−/− mice.