Time-related increase in mitochondrial superoxide production, biomolecule damage and antioxidant enzyme activities in cortical astrocyte cultures

According to the free radical theory of aging, biological senescence processes develop from a general failure to maintain organism's homeostasis, probably due to oxidative stress. The brain is particularly susceptible to oxidative damage, and astrocytes are chiefly responsible for its antioxidant defense. Here we evaluated and compared the enzymatic antioxidant activities, mitochondrial superoxide production, and oxidative damage in biomolecule in cortex astrocytes from newborn Wistar rats maintained for 10-13 or 40-47 days in culture. We show that, besides an increase in antioxidant enzyme activities in matured astrocyte cultures, there was an increase in lipoperoxidation and in protein oxidation, probably due to an increase in mitochondrial electron transport chain superoxide production. This could indicate that the increasing in defense mechanisms was not sufficient to avoid oxidative biomolecule damage during maturation.