Sasaki J C, Arey J, Eastmond D A, Parks K K, Grosovsky A J
Environmental Toxicology Graduate Program, University of California, Riverside 92521, USA.
Mutat Res. 1997 Sep 18;393(1-2):23-35. doi: 10.1016/s1383-5718(97)00083-1.
The genotoxic risks from exposure to polycyclic aromatic hydrocarbons (PAH) have long been recognized. Less well understood are the potential genotoxic risks of the atmospheric reaction products of this class of compounds. In this investigation, we have utilized several human cell genotoxicity assays to evaluate naphthalene, phenanthrene, and their atmospheric reaction products 1-nitronaphthalene, 2-nitronaphthalene, 1-hydroxy-2-nitronaphthalene, 2-hydroxy-1-nitronaphthalene, 1,4-naphthoquinone and 2-nitrodibenzopyranone. In addition, reaction products of naphthalene were generated in a 6700-1 Teflon environmental chamber, collected on a solid adsorbent, extracted and fractionated by normal-phase HPLC. Individual fractions were then analyzed using GC-MS, and tested for genotoxicity. Genotoxicity was determined using the human B-lymphoblastoid cell line, MCL-5, which expresses several transfected P450 and epoxide hydrolase genes. Mutagenicity was evaluated at both the heterozygous tk locus and the hemizygous hprt locus, permitting detection of both intragenic and chromosomal scale mutational events. Test compounds were also screened using the CREST modified micronucleus assay. Genotoxicity results indicate that 2-nitronaphthalene and 2-nitrodibenzopyranone possess greater mutagenic potency than their parent compounds, and interestingly, both compounds induced significant increases in mutation frequency at tk but not hprt. These results suggest a mechanistic difference in human cell response as compared to bacteria, where both compounds were previously shown to induce point mutations in the Salmonella reversion assay. The genotoxicity of 2-nitronaphthalene and 2-nitrodibenzopyranone in human cells, together with their high concentrations in ambient air relative to nitro-PAH directly emitted from combustion sources, emphasizes the need to consider atmospheric reaction products of PAH in genotoxicity assessments.
长期以来，人们一直认识到接触多环芳烃（PAH）会带来基因毒性风险。对于这类化合物的大气反应产物的潜在基因毒性风险，人们了解得较少。在本研究中，我们利用了几种人类细胞基因毒性检测方法来评估萘、菲及其大气反应产物1-硝基萘、2-硝基萘、1-羟基-2-硝基萘、2-羟基-1-硝基萘、1,4-萘醌和2-硝基二苯并吡喃酮。此外，在一个6700-1的特氟龙环境舱中生成萘的反应产物，收集在固体吸附剂上，通过正相高效液相色谱法进行提取和分离。然后使用气相色谱-质谱联用仪对各个馏分进行分析，并检测其基因毒性。使用表达几种转染的细胞色素P450和环氧化物水解酶基因的人类B淋巴母细胞系MCL-5来确定基因毒性。在杂合的胸苷激酶（tk）基因座和半合子次黄嘌呤磷酸核糖转移酶（hprt）基因座评估致突变性，从而能够检测基因内和染色体水平的突变事件。还使用CREST改良微核试验对受试化合物进行筛选。基因毒性结果表明，2-硝基萘和2-硝基二苯并吡喃酮比其母体化合物具有更高的致突变效力，有趣的是，这两种化合物在tk基因座而非hprt基因座诱导突变频率显著增加。这些结果表明，与细菌相比，人类细胞反应存在机制差异，此前在沙门氏菌回复突变试验中已表明这两种化合物在细菌中均诱导点突变。2-硝基萘和2-硝基二苯并吡喃酮在人类细胞中的基因毒性，以及它们在环境空气中相对于燃烧源直接排放的硝基多环芳烃的高浓度，强调了在基因毒性评估中需要考虑多环芳烃的大气反应产物。
