Effect of vitamin E on arachidonic acid peroxidation and its binding to Chinese hamster V79 cell DNA.
Following 24 h incubation in standard culture medium (containing 2 microM of arachidonic acid, AA), and 10 and 20 microM supplemented AA, approx. 55, 40 and 33%, respectively, of the fatty acid was incorporated into Chinese hamster V79 cell lipids. The AA content of cells increased 5 to 7-fold with the 10 and 20 microM supplementations of AA and, there was a correspondingly marked decrease in the proportion of AA incorporated into phospholipids (94 vs. 50 and 32%), whereas an increased percentage of AA was recovered in triacylglycerols (1 vs. 30 and 50%) and free fatty acids (1 vs. 3 and 8%). AA at 12 and 22 microM induced a 50 and 80% increase, respectively, in cellular content of thiobarbituric acid reactive substances (TBARS), an indication of increased peroxidation of cell lipids. This formation of TBARS was inhibited by vitamin E but not by indomethacin or SKF-525. Binding of [3H]AA-derived counts to DNA increased in parallel to the levels of cellular lipid peroxidation. Vitamin E added to the culture medium at 10(-4) M was readily taken up by the cells within 48 h and significantly reduced both lipid peroxidation and binding of AA-derived counts to DNA, without affecting AA uptake. Cell vitamin E content was significantly reduced following 24 h incubation in the presence of 10 and 20 microM supplemented AA. This study indicates that products of lipid peroxidation can bind to DNA in cultured cells, and points to a potential cyto- and geno-toxic risk posed by increased cellular AA content relative to anti-oxidant defenses.
Zhang
J R
JR
Institute for Toxicology, University of Southern California, Los Angeles 90033.
Sevanian
A
A
D000818:Animals; D001095:Arachidonic Acids / Q000378:metabolism*; D002460:Cell Line; D006224:Cricetinae; D004247:DNA / Q000378:metabolism*; D007213:Indomethacin / Q000494:pharmacology; D007700:Kinetics; D050356:Lipid Metabolism; D015227:Lipid Peroxidation / Q000187:drug effects; D011335:Proadifen / Q000494:pharmacology; D014810:Vitamin E / Q000494:pharmacology*
D001095:Arachidonic Acids; D014810:Vitamin E; D004247:DNA; D011335:Proadifen; D007213:Indomethacin