Three pairs of parental (q + ) and established mitochondrial DNAdepleted (q 0 ) cells, derived frombone, lungandmuscle were used to verify the influence of the nuclear background and the lack of efficient mitochondrial respiratory chain on antioxidant defences and homeostasis of intracellular reactive oxygen species (ROS). Mitochondrial DNA deple-tion significantly lowered glutathione reductase activity, glutathione (GSH) content, and consistently altered the GSH 2 : oxidized glutathione ratio in all of theq 0 cell lines, albeit todiffering extents, indicating themost oxidized redox state inboneq 0 cells
