Zhang J R, Sevanian A
Institute of Toxicology, School of Pharmacy, University of Southern California, Los Angeles 90033.
Toxicol Appl Pharmacol. 1993 Aug;121(2):193-202. doi: 10.1006/taap.1993.1145.
Chinese hamster lung fibroblasts (V79 cells) were exposed to 2, 20, 160, and 200 microM arachidonic acid (AA). At 20 microM, a stimulatory effect on cell growth was observed, while at 200 microM, an inhibitory effect was found. AA at 160 and 200 microM induced a 10- to 12-fold increase of 6-thioguanine-resistant mutants in V79 cells, whereas increased alkaline labile sites on DNA were consistently produced only with 200 microM treatment doses. The induction of alkaline labile lesions was partially inhibited in the presence of an antioxidant NDGA. [3H]AA metabolism in cells was examined by HPLC analysis following reductive transmethylation of the cell lipid extracts. Two fractions corresponding to [3H]AA-derived peroxidation products were identified by HPLC-radiochromatography and analyzed by mass spectrometry. Quantitative evaluation of the radioactivity associated with these peaks revealed an increase in [3H]AA peroxidation products when cells were exposed to increasing amounts of AA. The AA-dependent stimulation of lipid peroxidation product formation was partially inhibited when cells were treated in the presence of NDGA. The results provide evidence that substantially enlarged AA pools in cells may induce genotoxic effects mediated through increased endogenous lipid peroxidation products.
将中国仓鼠肺成纤维细胞（V79细胞）暴露于2、20、160和200微摩尔的花生四烯酸（AA）中。在20微摩尔时，观察到对细胞生长有刺激作用，而在200微摩尔时，则发现有抑制作用。160和200微摩尔的AA可使V79细胞中6-硫鸟嘌呤抗性突变体增加10至12倍，而仅在200微摩尔处理剂量下才持续产生DNA上碱性不稳定位点的增加。在抗氧化剂去甲二氢愈创木酸（NDGA）存在的情况下，碱性不稳定损伤的诱导受到部分抑制。通过对细胞脂质提取物进行还原甲基化后，采用高效液相色谱（HPLC）分析来检测细胞中[3H]AA的代谢情况。通过HPLC放射性色谱法鉴定出与[3H]AA衍生的过氧化产物相对应的两个组分，并通过质谱进行分析。对与这些峰相关的放射性进行定量评估发现，当细胞暴露于越来越多的AA时，[3H]AA过氧化产物增加。当在NDGA存在的情况下处理细胞时，AA依赖性脂质过氧化产物形成的刺激作用受到部分抑制。结果提供了证据，表明细胞中大量扩大的AA库可能通过增加内源性脂质过氧化产物介导遗传毒性作用。
