Interlaboratory Evaluation of Rodent Pulmonary Responses to Engineered Nanomaterials: The NIEHS Nano GO Consortium

Background: Engineered nanomaterials (ENMs) have potential benefits, but they also present safety concerns for human health. Interlaboratory studies in rodents using standardized protocols are needed to assess ENM toxicity. Methods: Four laboratories evaluated lung responses in C57BL/6 mice to ENMs delivered by oropharyngeal aspiration (OPA), and three labs evaluated Sprague-Dawley (SD) or Fisher 344 (F344) rats following intratracheal instillation (IT). ENMs tested included three forms of titanium dioxide (TiO2) [anatase/rutile spheres (TiO2-P25), anatase spheres (TiO2-A), and anatase nanobelts (TiO2-NBs)] and three forms of multiwalled carbon nanotubes (MWCNTs) [original (O), purified (P), and carboxylic acid “functionalized� (F)]. One day after treatment, bronchoalveolar lavage fluid was collected to determine differential cell counts, lactate dehydrogenase (LDH), and protein. Lungs were fixed for histopathology. Responses were also examined at 7 days (TiO2 forms) and 21 days (MWCNTs) after treatment. Results: TiO2-A, TiO2-P25, and TiO2-NB caused significant neutrophilia in mice at 1 day in three of four labs. TiO2-NB caused neutrophilia in rats at 1 day in two of three labs, and TiO2-P25 and TiO2-A had no significant effect in any of the labs. Inflammation induced by TiO2 in mice and rats resolved by day 7. All MWCNT types caused neutrophilia at 1 day in three of four mouse labs and in all rat labs. Three of four labs observed similar histopathology to O-MWCNTs and TiO2-NBs in mice. Conclusions: ENMs produced similar patterns of neutrophilia and pathology in rats and mice. Although interlaboratory variability was found in the degree of neutrophilia caused by the three types of TiO2 nanoparticles, similar findings of relative potency for the three types of MWCNTs were found across all laboratories, thus providing greater confidence in these interlaboratory comparisons

The Glutathione Synthesis Gene <i>Gclm</i> Modulates Amphiphilic Polymer-Coated CdSe/ZnS Quantum Dot–Induced Lung Inflammation in Mice

<div><p>Quantum dots (QDs) are unique semi-conductor fluorescent nanoparticles with potential uses in a variety of biomedical applications. However, concerns exist regarding their potential toxicity, specifically their capacity to induce oxidative stress and inflammation. In this study we synthesized CdSe/ZnS core/shell QDs with a tri-n-octylphosphine oxide, poly(maleic anhydride-alt-1-tetradecene) (TOPO-PMAT) coating and assessed their effects on lung inflammation in mice. Previously published <i>in vitro</i> data demonstrated these TOPO-PMAT QDs cause oxidative stress resulting in increased expression of antioxidant proteins, including heme oxygenase, and the glutathione (GSH) synthesis enzyme glutamate cysteine ligase (GCL). We therefore investigated the effects of these QDs <i>in vivo</i> in mice deficient in GSH synthesis (<i>Gclm</i> +/− and <i>Gclm</i> −/− mice). When mice were exposed via nasal instillation to a TOPO-PMAT QD dose of 6 µg cadmium (Cd) equivalents/kg body weight, neutrophil counts in bronchoalveolar lavage fluid (BALF) increased in both <i>Gclm</i> wild-type (+/+) and <i>Gclm</i> heterozygous (+/−) mice, whereas <i>Gclm</i> null (−/−) mice exhibited no such increase. Levels of the pro-inflammatory cytokines KC and TNFα increased in BALF from <i>Gclm</i> +/+ and +/− mice, but not from <i>Gclm</i> −/− mice. Analysis of lung Cd levels suggested that QDs were cleared more readily from the lungs of <i>Gclm</i> −/− mice. There was no change in matrix metalloproteinase (MMP) activity in any of the mice. However, there was a decrease in whole lung myeloperoxidase (MPO) content in <i>Gclm</i> −/− mice, regardless of treatment, relative to untreated <i>Gclm</i> +/+ mice. We conclude that in mice TOPO-PMAT QDs have <i>in vivo</i> pro-inflammatory properties, and the inflammatory response is dependent on GSH synthesis status. Because there is a common polymorphism in humans that influences GCLM expression, these findings imply that humans with reduced GSH synthesis capabilities may be more susceptible to the pro-inflammatory effects of QDs.</p></div

The safer chemical design game. Gamification of green chemistry and safer chemical design concepts for high school and undergraduate students

<p>Green chemistry can strongly attract students to chemistry. We, therefore, developed a green chemistry educational game that motivates students at the undergraduate and advanced high school levels to consider green chemistry and sustainability concerns as they design a hypothetical, chemical product. The game is intended for incorporation into any chemistry course for majors and non-majors that teaches sustainability and/or the Principles of Green Chemistry at the undergraduate level. The game is free of charge and encourages students to think like professional chemical designers and to develop a chemical product with respect to function and improved human and environmental health. This computer simulation has been assessed by educators and can be seamlessly integrated into an existing curriculum.</p

Lung matrix metalloproteinase activity and myeloperoxidase content.

<p>The effect of TOPO-PMAT QD administration on A) <b>matrix metalloproteinase (</b>MMP) activity and B) <b>myeloperoxidase</b> (MPO) content. Data represent the mean ± S.E.M. of 4 replicates ** = p<0.01 relative to saline treated mice.</p

mRNA expression of inflammatory cytokine genes as measured by qRT-PCR.

<p>The effects of saline or TOPO-PMAT QD administration on A) <i>Il1β</i>, B) <i>Mcp1</i>, C) <i>Tnfα</i>, D) <i>Gmcsf</i> and E) <i>KC</i> mRNA expression are shown. Data represent the mean ± S.E.M. of the indicated number of replicates in each bar.</p