Antioxidants and Longer Life for Mice
Mice engineered to produce elevated levels of an antioxidant enzyme in their mitochondria lived longer and exhibited less heart disease and other age-related declines, a new study published online in Science Express finds. This work supports the still somewhat controversial idea that antioxidant enzymes can have beneficial effects on mammalian lifespan.
Samuel Schriner and colleagues generated transgenic mice that overexpress the enzyme catalase in mitochondria. Catalase acts as an antioxidant by removing damaging hydrogen peroxide that is generated from reactive, negatively charged oxygen species.
Cellular oxidative damage and age-related decline in the heart and cataracts were reduced and lifespan increased by nearly 20 percent in the mice with elevated catalase levels in their mitochondria, the authors report.
This work supports the free radical theory of aging in which reactive, negatively charged oxygen species attack molecules and cause the functional decline of organ systems that eventually leads to death. The study also reinforces the importance of mitochondria as a source of these free radicals, the authors say.
Daniel B. Kane
9 May 2005