Development of enzyme-linked immunosorbent assay for 8-iso-prostaglandin F2α, a biomarker of oxidative stress in vivo, and its application to the quantification in aged rats

8-iso-Prostaglandin F-2 alpha (8-iso-PGF(2 alpha)) is one of the isoprostanes that are mainly generated nonenzymatically in vivo from arachidonic acid through free radical-induced lipid peroxidation. To assess oxidative stress in vivo, we developed a quantitative enzyme-linked immumosorbent assay (ELISA) for 8-iso-PGF(2 alpha). A sensitive calibration curve allowed the quantification of the amounts from 0.23 pg to 98.4 pg with 4.7 pg of 50% displacement in one assay. The ELISA method was applied to the measurement of the plasma levels of 8-iso-PGF(2 alpha). in young rats (4-8 weeks of age) and aged rats (106-123 weeks). The average level of esterified form in the plasma from aged rats was 30.6-fold higher than that in the plasma from young rats, reflecting the enhanced status of oxidative stress in aged animals. In addition, the aged rats exhibited higher levels of this F-2-isoprostane esterified to lipids from liver and kidney, suggesting local oxidative injury in specific organs. These results indicate the utility and accuracy of our ELISA for 8-iso-PGF(2 alpha). as a biomarker in vivo to assess systemic oxidative stress in animals or humans as well as oxidative injury at local sites. (C) 2009 Elsevier B.V. All rights reserved.