Changes in antioxidant enzyme expression in response to hydrogen peroxide in rat astroglial cells

Oxidative stress has been causally linked to a variety of neurodegenerative diseases. To clarify the role of the antioxidant enzyme (AOE) system in ox idative brain damage primary cultures of rat astroglial cells were exposed to hydrogen peroxide (H2O2) Expression of AOEs and several parameters for c ell viability and functionality were measured. In our experiments astrocyte s responded to low concentrations of H2O2 exposure with a pronounced genera tion of ROS which ran parallel with induction of lipid peroxidation. This d istinct oxidative stress was not reflected in cell viability or functionali ty parameters measured. Cytotoxicity, a decrease in glutathione content of astrocytes, and impairment of mitochondrial functions became obvious only f or higher concentrations of H2O2. After H2O2 exposure catalase, manganese s uperoxide dismutase, and glutathione peroxidase expression levels were foun d to be increased, whereas copper/zinc superoxide dismutase mRNA expression was not affected. These data indicate that the AOE system of astrocytes ca n be directly regulated by oxidative stress and may thus contribute to prot ection of cells against oxidative insults.