Tritiated Water Induces Toxicity in Human Umbilical Vein Vascular Endothelial Cells via IL8

Assessing tritium contamination in Thailand's rainwater: A study of environmental monitoring and nuclear surveillance

Tritium, whether naturally occurring or caused by human nuclear activity, can result in a large amount of tritium contamination in the environment, especially in the water cycle, causing a high concentration of tritium in rainfall. The objective of this research was to measure the level of tritium in the environment from rainfall in two different areas as a basis for monitoring tritium contamination in the environment. Rainwater samples were collected in Thailand every 24 h for a period of 1 year during 2021-2022 at the Kasetsart University Station, Sriracha Campus, Chonburi province and at the Mae Hia Agricultural Meteorological Station, Chiang Mai province. The tritium levels were measured in rainwater samples using the electrolytic enrichment method combined with liquid scintillation counting. The chemical composition of the rainwater was analyzed based on ion chromatography. The results (presented with ± combined uncertainty) showed that the tritium content in the rainwater samples at Kasetsart University Station Sriracha Campus was in the range 0.9 ± 0.2-1.6 ± 0.3 TU (0.11 ± 0.02-0.19 ± 0.03 Bq.L^-1). The mean concentration was 1.0 ± 0.2 TU (0.12 ± 0.03 Bq.L^-1). The most common ions found in the rainwater samples were SO₄^2-, Ca²⁺, and NO₃^-, with mean concentrations of 1.52 ± 0.82, 1.08 ± 0.51, and 1.05 ± 0.78 mg.L^-1, respectively. The tritium content in rainwater collected from the Mae Hia Agricultural Meteorological Station was in the range 1.6 ± 0.2-4.9 ± 0.4 TU (0.19 ± 0.02-0.58 ± 0.05 Bq.L^-1). The mean concentration was 2.4 ± 0.4 TU (0.28 ± 0.05 Bq.L^-1). The most common ions found in the rainwater were NO₃^-, Ca²⁺, and SO₄^2-, with mean concentrations of 1.21 ± 1.02, 0.67 ± 0.43, and 0.54 ± 0.41 mg.L^-1, respectively. The tritium concentration in the rainwater at both stations differed but remained at a natural level (less than 10 TU). There was no correlation between the tritium concentration and the chemical composition of the rainwater. The tritium levels obtained from this study could be used as a basis for reference and monitoring of future environmental changes due to nuclear accidents or activities, both domestically and internationally.

Transcriptome Analysis of the Immortal Human Keratinocyte HaCaT Cell Line Damaged by Tritiated Water

Radioactive elements, such as tritium, have been released into the ocean in large quantities as a result of the reactor leakage accident. In this study, an MTT assay demonstrated that the viability of HacaT cells decreased after tritiated water treatment. Bioinformatics analysis was used to analyze gene changes in the HacaT cells. The sequencing results showed 267 significantly differentially expressed genes (DEGs), and GO enrichment analysis showed that the DEGs were mainly divided into three parts. The KEGG pathway analysis showed that the up-regulated DEGs were involved in Wnt and other pathways, while the down-regulated DEGs were involved in Jak–STAT and others. A Western blot assay was used to verify the parts of the sequencing results. This study was the first to explore the mechanism of tritiated water on HacaT cells using Transcriptome analysis. The results will provide a theoretical basis for the study of tritiated water hazard mechanisms.

Activation of angiotensin II type 2 receptor attenuates lung injury of collagen-induced arthritis by alleviating endothelial cell injury and promoting Ly6Clo monocyte transition

As one of the most frequent extra-articular manifestations of rheumatoid arthritis (RA), interstitial lung disease (ILD) is still challenging due to unrevealed pathophysiological mechanism. To address this question, in the present study, we used the classical collagen-induced arthritis (CIA) mouse model to determine the related-immune mechanism of lung injury and possible pharmacological treatment for RA-ILD. At the peak of arthritis, we found CIA mice developed apparent lung injury, characterized by interstitial thickening, inflammatory cell infiltration, and lymphocyte follicle formation. Additionally, the endothelial injury occurred as the number of endothelial cells (ECs) and their CD31 expression decreased. Along with those, monocytes, predominantly Ly6C^hi monocytes with pro-inflammatory phenotype, were also increased. While in the remission period of arthritis, ECs gradually increased with retrieved CD31 expression, leading to decreased infiltrating monocytes, but boosted Ly6C^lo population. Ly6C^lo monocytes were prone to locate around damaged ECs, promoted ECs proliferation and vascular tube formation, and lessened the expression of adhesion molecules. In addition, we evaluated angiotensin II type 2 receptor (Agtr2), which has been demonstrated to be protective against lung injury, could be beneficial in RA-ILD. We found elevated Agtr2 in CIA lung tissue, and activation of Agtr2, within its specific agonist C21, alleviated the pulmonary inflammation in vivo, reduced ECs injury, and promoted monocytes conversion from Ly6C^hi to Ly6C^lo monocytes in vitro. Our data reveal a potential pathological mechanism of RA-ILD that involves ECs damage and inflammatory monocytes infiltration and provide a potential drug target, Agtr2, for RA-ILD treatment.

A 3D In Vitro Model of the Human Airway Epithelium Exposed to Tritiated Water: Dosimetric Estimate and Cytotoxic Effects

Tritium has been receiving worldwide attention, particularly because of its production and use in existing fission reactors and future nuclear fusion technologies, leading to an increased risk of release in the environment. Linking human health effects to low-dose tritium exposures presents a challenge for many reasons. Among these: biological effects strongly depend on the speciation of tritiated products and exposure pathway; large dosimetric uncertainties may exist; measurements using in vitro cell cultures generally lack a description of effects at the tissue level, while large-scale animal studies might be ethically questionable and too highly demanding in terms of resources. In this context, three-dimensional models of the human airway epithelium are a powerful tool to investigate potential toxicity induced upon inhalation of radioactive products in controlled physiological conditions. In this study we exposed such a model to tritiated water (HTO) for 24 h, with a range of activity levels (up to ∼33 kBq µl-1 cm-2). After the exposures, we measured cell viability, integrity of epithelial layer and pro-inflammatory response at different post-exposure time-points. We also quantified tritium absorption and performed dosimetric estimates considering HTO passage through the epithelial layer, leading to reconstructed upper limits for the dose to the tissue of less than 50 cGy cumulative dose for the highest activity. Upon exposure to the highest activity, cell viability was not decreased; however, we observed a small effect on epithelial integrity and an inflammatory response persisting after seven days. These results represent a reference condition and will guide future experiments using human airway epithelium to investigate the effects of other peculiar tritiated products.