Division of Environmental Health Sciences, University of California, Berkeley, CA 94720, USA.
Chem Res Toxicol. 2012 Sep 17;25(9):1885-92. doi: 10.1021/tx3001708. Epub 2012 Aug 10.
In vitro testing is a common first step in assessing combustion-generated and engineered nanoparticle-related health hazards. Commercially available viability assays are frequently used to compare the toxicity of different particle types and to generate dose-response data. Nanoparticles, well-known for having large surface areas and chemically active surfaces, may interfere with viability assays, producing a false assessment of toxicity and making it difficult to compare toxicity data. The objective of this study is to measure the extent of particle interference in two common viability assays, the MTT reduction and the lactate dehydrogenase (LDH) release assays. Diesel particles, activated carbon, flame soot, oxidized flame soot, and titanium dioxide particles are assessed for interactions with the MTT and LDH assay under cell-free conditions. Diesel particles, at concentrations as low as 0.05 μg/mL, reduce MTT. Other particle types reduce MTT only at a concentration of 50 μg/mL and higher. The activated carbon, soot, and oxidized soot particles bind LDH to varying extents, reducing the concentration measured in the LDH assay. The interfering effects of the particles explain in part the different toxicities measured in human bronchial epithelial cells (16HBE14o). We conclude that valid particle toxicity assessments can only be assured after first performing controls to verify that the particles under investigation do not interfere with a specific assay at the expected concentrations.
体外测试是评估燃烧生成和工程纳米颗粒相关健康危害的常见第一步。商业上可用的生存能力测定法常用于比较不同颗粒类型的毒性，并产生剂量-反应数据。由于纳米颗粒具有大的表面积和化学活性表面，因此可能会干扰生存能力测定法，从而对毒性产生错误的评估，并且难以比较毒性数据。本研究的目的是测量两种常见生存能力测定法（MTT 减少和乳酸脱氢酶（LDH）释放测定法）中颗粒干扰的程度。在无细胞条件下，评估柴油机颗粒、活性炭、火焰烟尘、氧化火焰烟尘和二氧化钛颗粒与 MTT 和 LDH 测定法的相互作用。柴油机颗粒在低至 0.05μg/mL 的浓度下就会减少 MTT。其他颗粒类型仅在浓度为 50μg/mL 及更高时才会减少 MTT。活性炭、烟尘和氧化烟尘颗粒会在不同程度上结合 LDH，从而减少 LDH 测定法中测量到的浓度。颗粒的干扰作用部分解释了在人支气管上皮细胞（16HBE14o）中测量到的不同毒性。我们得出结论，只有在进行控制以验证所研究的颗粒在预期浓度下不会干扰特定测定法之后，才能确保进行有效的颗粒毒性评估。
