DECREASES IN PROTECTIVE ENZYMES CORRELATES WITH INCREASED OXIDATIVE DAMAGE IN THE AGING MOUSE-BRAIN

We used several biochemical assays to evaluate age-related changes in antioxidant enzyme levels vs. free-radical damage in the murine brain. We found levels of several free-radical scavenging enzymes in the bra ins of 24-month-old C57Bl male mice vs. 12-month-old animals were decr eased, including superoxide dismutase (SOD), catalase, and glutathione reductase (GSSG-Rd). In addition, we found concomitant increases in t he levels of several forms of free-radical damage including sensitivit y to lipid peroxidation as measured by the thiobarbituric acid test, p rotein oxidation as measured by glutamine synthetase (Gln Syn) activit y, as well as increases in oxidized glutathione (GSSG) levels, a measu re of oxidative stress. These data suggest that decreases in levels of enzymes which ordinarily protect neuronal cells against oxidative str ess with age may be responsible for increased levels of free-radical d amage in the murine brain, or that these enzymes themselves are suscep tible to inactivation by free radical molecules which increase with ag e in the brain.