Background: The value of relative biological effectiveness of tritium increases at low dose domain, which results in the suspicion of weighting factor of 1 for tritium after low dose exposure. Thus, present study was carried out to analyze the differences in the cellular responses at early and late period between low dose of tritium β-rays and γ-rays radiation.

Methods: MCF-10A cells were exposed to low dose of tritium β-rays or γ-rays, then cellular behaviors, such as DNA double strand breaks (DSBs), apoptosis, reactive oxygen species (ROS) level and inflammatory relevant gene expression were analyzed at early and late period post-irradiation.

Results: At early period the elimination of DSB foci produced by HTO is longer than γ-rays. High ROS level and a continual change of cell cycle distribution are observed in HTO radiation group. Based on the results of RNA sequencing, Ingenuity Pathway Analysis (IPA) indicates TNFR1 signaling and production of nitric oxide and ROS are activated as an acute response at 24 h post radiation. Moreover, it also shows a disturbance in cholesterol biosynthesis. The results of 30 days point that there is a lasting active inflammatory response, accompanying with a persistent high expression of relevant cytokines, such as TNF and IL1R.

Conclusion: Compared to an acute response induced by γ-rays, a persistent inflammatory response exists in HTO-irradiated cells when cultured for 30 days, which might be related to accumulation of tritium in the form of organically bound tritium (OBT) in cellular DNA or lipids.

背景：在低剂量范围内，tri的相对生物学有效性值会增加，这导致怀疑在低剂量暴露后tri的加权因子为1。因此，进行了本研究以分析低剂量β射线和γ射线辐射在早期和晚期的细胞反应的差异。

方法：将MCF-10A细胞暴露于低剂量的β射线或γ射线照射后，观察其DNA双链断裂（DSB），细胞凋亡，活性氧（ROS）水平和炎症相关基因表达等细胞行为。在辐照后的早期和晚期进行分析。

结果：早期消除HTO产生的DSB病灶的时间长于γ射线。在HTO辐射组中观察到较高的ROS水平和细胞周期分布的连续变化。基于RNA测序的结果，Ingenuity Pathway Analysis（IPA）表明TNFR1信号传导以及一氧化氮和ROS的产生在放射后24小时被激活为急性反应。此外，它还显示出胆固醇生物合成的紊乱。30天的结果表明，存在持续的主动炎症反应，并伴随着相关细胞因子（如TNF和IL1R）的持续高表达。

结论：与γ射线诱导的急性反应相比，HTO照射的细胞培养30天后存在持续的炎症反应，这可能与cellular以有机结合organic（OBT）的形式在细胞DNA中积累有关或脂质。