Lipid hydroperoxides TBARS assay

This test is used for both in vitro and in vivo determinations. It involves reacting thiobarbituric acid (TBA) with malondialdehyde (MDA), produced by lipid hydroperoxide decomposition, to form a red chromophore with peak absorbance at 532 nm (Fig. 10.1). The TBARS reaction is not specific. Many other substances, including other alkanals, proteins, sucrose, or urea, may react with TBA to form colored species that can interfere with this assay. 

In the second experiment, mice were irradiated with the highest dose from the dose-response experiment. Concentrations of lipid hydroperoxides and lipophilic antioxidants were measured simultaneously on single skin samples from irradiated and non-irradiated sides of each mouse. The lipid hydroperoxide assay directly measured lipid peroxidation and thus was superior to the TBARS assay, which is indirect. Lipid-peroxyl radicals have been linked to chemically induced cutaneous carcinogenesis [31] as well as to UV-light-induced cutaneous carcinogenesis [32],... 

The immediate appearance of lipid hydroperoxides after irradiation in this study contrasts with several other studies, which have either reported no increase in lipid-peroxidation products in skin after UV irradiation [21] or an increase only several hours after irradiation [27-29], In these studies the background level of lipid-peroxidation products has been high, even in control, non-irradiated skin. In contrast, in our experiments lipid hydroperoxides were undetectable before irradiation, but appeared at very high concentrations in skin immediately after irradiation. The discrepancies between various studies may be due to differences in technique. The HPLC-chemiluminescence assay used in the present study is specific for lipid hydroperoxides, and has less potential for artifact than the TBARS assay, which is known to suffer from many possibilities for artifact [30] -... 

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