a. DNA Oxidation Analysis

    Most of the attacks on the stable DNA come from the hydroxyl radical, OH.. The OH. can attack guanine at its C-8 position to yield an oxidation product, 8-hydroxydeoxyguanosine (8-OHdG), which can be quantified using a competitive enzyme-linked immunosorbent assays (ELISA) kit (New 8-OHdOG Check, Japan Institute for the Control of Aging, Japan). The underlying principle for these immunoassays is based on highly specific interaction of the target PAH analyte with a corresponding antibody, followed by the production of a colorimetric/fluorometric response to allow quantitative determination of 1-NP. Figure 3 summarizes the mechanism of ELISA.

b. Lipid Peroxidation Analysis

    Lipid peroxidation reflects a chain reaction between polyunsaturated fatty acids and ROS producing lipid peroxides and hydrocarbon polymers that are both highly toxic to the cell. Malonyldialdehyde (MDA) is an end product of peroxidation of polyunsaturated fatty acids and related esters. MDA is spectrophotometrically quantified by reacting with thiobarbituric acid (TBA), forming a colored complex with a maximum absorbance at 532 nm [7].