It is well established that toxicological evaluation of engineered nanomaterials (NMs) is vital to ensure the health and safety of those exposed to them. Further, there is a distinct need for the development of advanced physiologically relevant in vitro techniques for NM hazard prediction due to the limited predictive power of current in vitro models and the unsustainability of conducting nano-safety evaluations in vivo. Thus, the purpose of this study was to develop alternative in vitro approaches to assess the potential of NMs to induce genotoxicity by secondary mechanisms. This was first undertaken by a conditioned media-based technique, whereby cell culture media was transferred from differentiated THP-1 (dTHP-1) macrophages treated with γ-Fe2O3 or Fe3O4 superparamagnetic iron oxide nanoparticles (SPIONs) to the bronchial cell line 16HBE14o−. Secondly construction and SPION treatment of a co-culture model comprising of 16HBE14o− cells and dTHP-1 macrophages. For both of these approaches no cytotoxicity was detected and chromosomal damage was evaluated by the in vitro micronucleus assay. Genotoxicity assessment was also performed using 16HBE14o− monocultures, which demonstrated only γ-Fe2O3 nanoparticles to be capable of inducing chromosomal damage. In contrast, immune cell conditioned media and dual cell co-culture SPION treatments showed both SPION types to be genotoxic to 16HBE14o− cells due to secondary genotoxicity promoted by SPION-immune cell interaction. The findings of the present study demonstrate that the approach of using single in vitro cell test systems precludes the ability to consider secondary genotoxic mechanisms. Consequently, the use of multi-cell type models is preferable as they better mimic the in vivo environment and thus offer the potential to enhance understanding and detection of a wider breadth of potential damage induced by NMs.

中文翻译：

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工程纳米材料诱导的遗传毒性的体外二级机制的体外检测

公认的是，工程纳米材料（NMs）的毒理学评估对于确保接触纳米材料的人们的健康和安全至关重要。此外，由于当前体外模型的有限预测能力以及在体内进行纳米安全性评估的不可持续性，迫切需要开发先进的生理相关的体外技术来进行NM危害预测。因此，本研究的目的是开发替代的体外方法，以评估NMs通过次级机制诱导遗传毒性的潜力。这首先是通过基于条件培养基的技术进行的，将细胞培养基从经γ-Fe2O3或Fe3O4超顺磁性氧化铁纳米颗粒（SPIONs）处理的分化的THP-1（dTHP-1）巨噬细胞转移到支气管细胞系16HBE14o- 。其次，构建和SPION处理包含16HBE140-细胞和dTHP-1巨噬细胞的共培养模型。对于这两种方法，均未检测到细胞毒性，并且通过体外微核试验评估了染色体损伤。还使用16HBE14o-单培养进行了基因毒性评估，该研究仅证明γ-Fe2O3纳米颗粒能够诱导染色体损伤。相反，免疫细胞条件培养基和双细胞共培养SPION处理显示两种SPION类型均对16HBE14o-细胞具有遗传毒性，这归因于SPION-免疫细胞相互作用促进的继发性遗传毒性。本研究的发现表明，使用单个体外细胞测试系统的方法排除了考虑继发性遗传毒性机制的能力。所以，