Embryotoxicology Section, Indian Institute of Toxicology Research, Mahatma Gandhi Marg, Lucknow 226 001, Uttar Pradesh, India; Council of Scientific and Industrial Research, New Delhi, India.
Chemosphere. 2010 Apr;79(5):577-87. doi: 10.1016/j.chemosphere.2010.01.054. Epub 2010 Feb 25.
Benzene, toluene and xylene are monocyclic aromatic hydrocarbon compounds, used both as individual compound and as mixtures, in industry as well as household. Previous studies involving exposures to these compounds, individually, have shown that benzene was more toxic compared to toluene or xylene. Here, we tested a working hypothesis that toluene and/or xylene in a mixture containing benzene affect benzene induced toxicity in a non-target organism, Drosophila melanogaster. We exposed D. melanogaster larvae transgenic for hsp70, hsp83 or hsp26 and wild type (Oregon R strain) larvae to 25.0-100.0mM benzene, 25.0-100.0mM toluene and 25.0-100mM xylene, individually or in mixtures. Subsequently, we examined the expression of stress genes (encoding heat shock proteins, hsps), generation of reactive oxygen species (ROS), induction of anti-oxidant stress markers and emergence of flies under treatment as well as control conditions. We observed that all these endpoints were significantly altered in all the treatment groups compared to their respective controls. However, the magnitude of toxicity of a benzene-toluene (BT) or benzene-xylene (BX) or benzene-toluene-xylene (BTX) mixture was significantly lower in the organism than that of individual chemical. Our results also show the modulation of toluene toxicity by xylene. Present study suggests antagonistic effect of xylene and toluene on benzene toxicity and additive/synergistic effect of xylene on toluene induced toxicity. Thus, expression of stress genes may be used as an assay for detection of early cellular toxicity. Further, our study supports the use of Drosophila as an alternative animal model for first tier screening of adverse effects of chemical mixtures.
苯、甲苯和二甲苯是单环芳烃化合物，既作为单个化合物，也作为混合物，在工业和家庭中都有使用。之前涉及这些化合物单独暴露的研究表明，与甲苯或二甲苯相比，苯的毒性更大。在这里，我们检验了一个工作假设，即在含有苯的混合物中，甲苯和/或二甲苯会影响非靶标生物黑腹果蝇中苯引起的毒性。我们将 hsp70、hsp83 或 hsp26 转基因的黑腹果蝇幼虫和野生型（Oregon R 品系）幼虫暴露于 25.0-100.0mM 苯、25.0-100.0mM 甲苯和 25.0-100mM 二甲苯中，单独或混合。随后，我们检查了应激基因（编码热休克蛋白，hsps）的表达、活性氧（ROS）的产生、抗氧化应激标志物的诱导以及在处理和对照条件下的果蝇出现情况。我们观察到，与各自的对照相比，所有这些终点在所有处理组中都显著改变。然而，与单一化学物质相比，苯-甲苯（BT）或苯-二甲苯（BX）或苯-甲苯-二甲苯（BTX）混合物的毒性明显降低。我们的研究结果还表明二甲苯对甲苯毒性的调制。本研究表明，二甲苯和甲苯对苯毒性具有拮抗作用，而二甲苯对甲苯诱导的毒性具有相加/协同作用。因此，应激基因的表达可以作为检测早期细胞毒性的一种检测方法。此外，我们的研究支持将黑腹果蝇用作替代动物模型，用于对化学混合物的不良影响进行第一级筛选。
