Technische Universität Dresden, School of Science, Faculty of Biology, Institute of Zoology, Chair of Molecular Cell Physiology and Endocrinology, Zellescher Weg 20b, 01217, Dresden, Germany.
Helmholtz-Zentrum Dresden-Rossendorf, Institute of Resource Ecology, Bautzner Landstraße 400, 01328, Dresden, Germany.
Toxicology. 2021 May 30;456:152771. doi: 10.1016/j.tox.2021.152771. Epub 2021 Apr 5.
Lanthanide (Ln) exposure poses a serious health risk to animals and humans. In this study, we investigated the effect of 10-10 M La, Ce, Eu, and Yb exposure onto the viability of rat renal NRK-52E cells in dependence on Ln concentration, exposure time, and composition of the cell culture medium. Especially, the influence of fetal bovine serum (FBS) and citrate onto Ln cytotoxicity, solubility, and speciation was investigated. For this, in vitro cell viability studies using the XTT assay and fluorescence microscopic investigations were combined with solubility and speciation studies using TRLFS and ICP-MS, respectively. The theoretical Ln speciation was predicted using thermodynamic modeling. All Ln exhibit a concentration- and time-dependent effect on NRK-52E cells. FBS is the key parameter influencing both Ln solubility and cytotoxicity. We demonstrate that FBS is able to bind Ln ions, thus, promoting solubility and reducing cytotoxicity after Ln exposure for 24 and 48 h. In contrast, citrate addition to the cell culture medium has no significant effect on Ln solubility and speciation nor cytotoxicity after Ln exposure for 24 and 48 h. However, a striking increase of cell viability is observable after Ln exposure for 8 h. Out of the four Ln elements under investigation, Ce is the most effective. Results from TRLFS and solubility measurements correlate well to those from in vitro cell culture experiments. In contrast, results from thermodynamic modeling do not correlate to TRLFS results, hence, demonstrating that big gaps in the database render this method, currently, inapplicable for the prediction of Ln speciation in cell culture media. Finally, this study demonstrates the importance and the synergistic effects of combining chemical and spectroscopic methods with cell culture techniques and biological methods.
镧系元素（Ln）暴露对动物和人类的健康构成严重威胁。在这项研究中，我们研究了 10-10 M La、Ce、Eu 和 Yb 暴露对依赖于 Ln 浓度、暴露时间和细胞培养液成分的大鼠肾 NRK-52E 细胞活力的影响。特别是，研究了胎牛血清（FBS）和柠檬酸盐对 Ln 细胞毒性、溶解度和形态的影响。为此，我们将 XTT 测定法的体外细胞活力研究与 TRLFS 和 ICP-MS 分别进行的溶解度和形态研究相结合，并使用热力学建模预测了理论 Ln 形态。所有 Ln 对 NRK-52E 细胞均表现出浓度和时间依赖性效应。FBS 是影响 Ln 溶解度和细胞毒性的关键参数。我们证明 FBS 能够结合 Ln 离子，从而在暴露 24 和 48 小时后促进 Ln 的溶解度并降低细胞毒性。相比之下，向细胞培养液中添加柠檬酸盐对暴露 24 和 48 小时后的 Ln 溶解度和形态以及细胞毒性没有显著影响。然而，暴露 8 小时后可观察到细胞活力明显增加。在所研究的四种 Ln 元素中，Ce 的效果最显著。TRLFS 和溶解度测量的结果与体外细胞培养实验的结果非常吻合。相反，热力学建模的结果与 TRLFS 结果不相关，这表明数据库中的巨大差距使得该方法目前无法应用于细胞培养液中 Ln 形态的预测。最后，这项研究证明了将化学和光谱方法与细胞培养技术和生物学方法相结合的重要性和协同作用。
