2000 年 46 巻 2 号 p. 75-80
It is assumed that oxidative stress due to reactive oxygen species (ROS) such as superoxide anion (·O2 -), hydrogen peroxide (H2O2) and hydroxyl radical (·OH) may result in oxidative damage to lipids and DNA. On the other hand, chromium(VI) compounds, potent carcinogens, are known to induce lipid peroxidation. However, it is not clear how Cr(VI) induces lipid peroxidation and DNA damage. In this article, in order to clarify the mechanism by which Cr(VI) enhances lipid peroxidation, the lipid-peroxidizing activity of Cr(IV) and Cr(V), Cr intermediates possibly produced in the reductive metabolism of Cr(VI), were compared with that of Cr(VI) and Cr(III), and the inhibitory effects of ROS scavengers on lipid peroxidation induced by Cr(IV) and Cr(V) were examined by incubating mouse liver homogenate with Cr and scavenger compounds. Cr(IV), Cr(V) and Cr(VI) compounds effectively enhanced lipid peroxidation of homogenate in this order. The lipid-peroxidizing effect of Cr(IV) was suppressed more remarkably by superoxide dismutase, catalase and formate, specific scavengers of ·O2 -, H2O2 and ·OH, respectively, than that of Cr(V), which is indicative of the involvement of ·O2 -, H2O2 and ·OH in lipid peroxidation stimulated by these Cr species. These results suggest the possible participation of Cr(IV), Cr(V), ·O2 -, H2O2 and ·OH in Cr(VI)-enhanced lipid peroxidation.
