Solid fuel combustion is an important source of the release of rare earth elements (REEs) into the ambient environment, resulting in potential adverse effects on human cardiovascular health. Our study aimed to identify reliable exposure biomarkers of REE intake and their potential role in blood pressure change. A total of 24 rats were administered with 14 REE chlorides at four doses (six rats per group). Fur samples were collected both before and after administration. Blood samples were collected after 12 weeks of REE intake. The REE concentrations in rat fur and blood samples were measured by inductively coupled plasma mass spectrometry. For each week, blood pressure, as well as heart rate and pulse pressure, were measured. The linear mixed-effect model was used to analyze the relationship between REE administration dose and blood pressure change. We found that the REE concentration in fur, but not blood, samples exhibited significant dose–response relationships with administration dose. It suggested that hair samples are a more efficient matrix for indicating the exposure level of a population to REEs than blood samples. However, there was no dose–response relationships between the administration dose and blood pressure change of rats, or with heart rate and pulse pressure for the 14 REEs. We also did not find a dose–response relationship between REE administration levels and plasma concentration of 8-hydroxy-2’-deoxyguanosine, as an important DNA oxidative stress damage biomarker. In conclusion, hair samples are more suitable as a sample type to reliably assess exposure to REEs than blood samples, and REEs did not have a direct adverse effect on blood pressure in our rat model.

中文翻译：

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稀土元素对血压及其暴露生物标志物的影响：来自动物实验的证据

固体燃料燃烧是稀土元素（REEs）释放的重要来源) 进入周围环境，从而对人类心血管健康产生潜在的不利影响。我们的研究旨在确定 REE 摄入量的可靠暴露生物标志物及其在血压变化中的潜在作用。总共 24 只大鼠以四次给药（每组 6 只大鼠）服用 14 种氯化稀土。在给药之前和之后收集毛皮样品。在摄入 REE 12 周后收集血样。通过电感耦合等离子体质谱法测量大鼠毛皮和血液样品中的 REE 浓度。每周测量血压以及心率和脉压。采用线性混合效应模型分析REE给药剂量与血压变化的关系。我们发现毛皮中的 REE 浓度，但不是血液，样品表现出与给药剂量显着的剂量反应关系。它表明，头发样本是一种更有效的矩阵，可用于指示人群对以下物质的暴露水平REE比血样。然而，对于14种REE，给药剂量与大鼠血压变化或心率和脉压之间没有剂量-反应关系。我们也没有发现 REE 给药水平与 8-羟基-2'-脱氧鸟苷的血浆浓度之间存在剂量反应关系，8-羟基-2'-脱氧鸟苷是一种重要的 DNA 氧化应激损伤生物标志物。总之，头发样本比血液样本更适合作为可靠评估REE暴露的样本类型，并且REE对我们的大鼠模型中的血压没有直接不利影响。