Tritium is a water-soluble hydrogen isotope that releases beta rays during decay. In nature, tritium primarily exists as tritiated water (HTO), and its main source is nuclear power/processing plants. In recent decades, with the development of nuclear power industry, it is necessary to evaluate the impact of tritium on organisms. In this study, fertilized zebrafish embryos are treated with different HTO concentrations (3.7 × 10³ Bq/ml, 3.7 × 10⁴ Bq/ml, 3.7 × 10⁵ Bq/ml). After treatment with HTO, the zebrafish embryos developed without evident morphological changes. Nevertheless, the heart rate increased and locomotor activity decreased significantly. In addition, RNA-sequencing shows that HTO can affect gene expressions. The differentially expressed genes are enriched through many physiological processes and intracellular signaling pathways, including cardiac, cardiovascular, and nervous system development and the metabolism of xenobiotics by cytochrome P450. Moreover, the concentrations of thyroid hormones in the zebrafish decrease and the expression of thyroid hormone-related genes is disordered after HTO treatment. Our results suggest that exposure to HTO may affect the physiology and behaviors of zebrafish through physiological processes and intracellular signaling pathways and provide a theoretical basis for ecological risk assessment of tritium.

氚是一种水溶性氢同位素，在衰变过程中会释放β射线。在自然界中，氚主要以氚化水 (HTO) 的形式存在，其主要来源是核电站/加工厂。近几十年来，随着核电工业的发展，有必要评估氚对生物体的影响。在本研究中，受精斑马鱼胚胎用不同的 HTO 浓度（3.7 × 10 ³ Bq/ml、3.7 × 10 ⁴ Bq/ml、3.7 × 10 ⁵Bq/毫升）。用 HTO 处理后，斑马鱼胚胎发育没有明显的形态变化。然而，心率增加，运动活动显着减少。此外，RNA 测序表明 HTO 可以影响基因表达。差异表达的基因通过许多生理过程和细胞内信号通路富集，包括心脏、心血管和神经系统发育以及细胞色素 P450 对异生物质的代谢。此外，斑马鱼体内甲状腺激素浓度降低，甲状腺激素相关基因表达紊乱。