Abstract
Astrocytes are one of the predominant glial cell types in the adult central nervous system functioning as both supportive and metabolic cells for the brain. Our objective in this experiment is to study the direct effects of hydrogen peroxide induced oxidative stress on astrocytes in culture. These astrocytes were derived from both an aged mouse strain (P8) and a matched control strain (R1). The astrocytes for both the P8 and R1 strains were treated with increasing concentrations of hydrogen peroxide. Our results showed that the oxidative stress had a similar effect in both strains of astrocytes; decreases in 3-(4,5-dimethylthiazol-2-yl)-2,2-diphenyltetrazolium bromide (MTT) and glial fibrillary acidic protein (GFAP) levels, and increases in terminal deoxynucleotidyltransferase-mediated dUTP nick end-labeling (TUNEL) staining, lactate dehydrogenase (LDH) staining, and superoxide dismutase (SOD), caspase-3 and B-cell lymphoma 2-associated protein X (bax) levels. At a hydrogen peroxide concentration of 400 microM , the differences of the above parameters between P8 cultures and R1 cultures were statistically significant (p<0.05). This strongly suggested that astrocytes derived from P8 and R1 strains reacted to oxidative stress with similar mechanisms and consequences. However, the mechanisms were not able to compensate for the oxidative stress in the P8 strain at a hydrogen peroxide concentration of 400 microM. The inability of the P8 astrocytes to counteract the oxidative stress might lead to inadequate protection from neuronal loss possibly resulting in significantly more astrocytic death. Our results suggested that the changes of astrocytes in peroxide detoxification may play a role in aging of the central nervous system, and further aging studies should examine the oxidative status of the samples.