Age-associated changes of superoxide dismutase and catalase activities in the rat brain

Oxygen free radicals have been proposed to be involved in the process of ag ing. Superoxide dismutase (SOD) and catalase are important for antioxidativ e defense. In this study, profiles of SOD, catalase, and their mRNA levels were investigated in the frontal, parietal, temporal and occipital lobes, s ubcortex and cerebellum of male Wistar rats at ages 1-21 months, The total SOD and Mn SOD activities increased with age and exhibited higher levels at 6 and 12 months but decreased thereafter. Activity of catalase showed a si milar trend and notably peaked at 12 months. The mRNA levels of Cu/Zn SOD, Mn SOD, and catalase remained constant in all areas tested (frontal, pariet al, temporal and occipital robes, and subcortex) except the cerebellum. Pos t-transcriptional regulation was involved in modulating the enzymes' activi ties during aging. Furthermore, the rate of mitochondrial generation of the superoxide anion (O-2(radical anion)) increased gradually with aging. Take n together, the results suggest that the increase of oxidative potential an d the loss of proper antioxidant defense in the rats appear to be highly in volved in the aging process of the brain. Copyright (C) 2000 National Scien ce Council, ROC and S. Karger AG. Basel.