Effect of internal contamination with tritiated water on the neoplastic colonies in the lungs, innate anti-tumour reactions, cytokine profile, and haematopoietic system in radioresistant and radiosensitive mice

Radiation Effects of Normal B-Lymphoblastoid Cells after Exposing Them to Low-Dose-Rate Irradiation from Tritium β-rays

The effects of tritium at low doses and low dose rates have received increasing attention due to recent developments in fusion energy and the associated risks of tritium releases into the environment. Mitochondria have been identified as a potential candidate for studying the effects of low-dose/low-dose-rate radiation, with extensive experimental results obtained using X-ray irradiation. In this study, irradiation experiments were conducted on normal B-lymphoblastoid cells using HTO at varying doses. When compared to X-ray irradiation, no significant differences in cell viability induced by different doses were observed. However, the results of ATP levels showed a significant difference between the irradiated sample at a dose of 500 mGy by tritium beta-rays and the sham-irradiated sample, while the levels obtained with X-ray irradiation were almost identical to the sham-irradiated sample. In contrast, ATP levels for both tritium beta-rays and X-rays at a dose of 1.0 Gy showed minimal differences compared to the sham-irradiated sample. Furthermore, distinct effects at 500 mGy were also confirmed in both ROS levels and apoptosis results obtained through tritium beta-ray irradiation. This suggests that mitochondria might be a potential sensitive target for investigating the effects of tritium beta-ray irradiation.

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.

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.