Mitochondrial alterations and a higher oxidative status in cultured fibroblast-like cells from senescence-accelerated mice

We studied changes in the quantity of reactive oxygen species (ROS) and the changes in mitochondrial morphology in cultured murine dermal fibroblast-like (MDF) cells from SAMP11 and SAMR1 mice. The quantity of ROS in the SAMP11 cells was greater than that in the SAMR1 cells after the 7th day in culture. We measured the enzymatic activity and mRNA quantity of the antioxidant enzymes (AOEs), but no changes that could account for the difference in ROS production between these two cell lines were found. Ultrastructural study revealed that mitochondria with degenerated cristae and an electron-dense matrix were increased in the SAMP11 cells with time. Differences in oxidative status between the two cell lines became obvious along with an increase in the morphologically abnormal mitochondria in the SAMP11 cells. This suggests that mitochondrial abnormalities are associated with a higher oxidative status.