Department of Biological Science, College of Sciences, Ibaraki University, Mito, Japan.
Department of Radiation Effects Research, National Institute of Radiological Sciences (NIRS), National Institutes for Quantum and Radiological Science and Technology (QST), Chiba, Japan.
Front Immunol. 2021 Oct 22;12:760322. doi: 10.3389/fimmu.2021.760322. eCollection 2021.
After the Fukushima Daiichi Nuclear Power Plant accident, there is growing concern about radiation-induced carcinogenesis. In addition, living in a long-term shelter or temporary housing due to disasters might cause unpleasant stress, which adversely affects physical and mental health. It's been experimentally demonstrated that "eustress", which is rich and comfortable, has beneficial effects for health using mouse models. In a previous study, mice raised in the enriched environment (EE) has shown effects such as suppression of tumor growth and enhancement of drug sensitivity during cancer treatment. However, it's not yet been evaluated whether EE affects radiation-induced carcinogenesis. Therefore, to evaluate whether EE suppresses a radiation-induced carcinogenesis after radiation exposure, in this study, we assessed the serum leptin levels, radiation-induced DNA damage response and inflammatory response using the mouse model. In brief, serum and tissues were collected and analyzed over time in irradiated mice after manipulating the raising environment during the juvenile or adult stage. To assess the radiation-induced DNA damage response, we performed immunostaining for phosphorylated H2AX which is a marker of DNA double-strand break. Focusing on the polarization of macrophages in the inflammatory reaction that has an important role in carcinogenesis, we performed analysis using tissue immunofluorescence staining and RT-qPCR. Our data confirmed that EE breeding before radiation exposure improved the responsiveness to radiation-induced DNA damage and basal immunity, further suppressing the chronic inflammatory response, and that might lead to a reduction of the risk of radiation-induced carcinogenesis.
福岛第一核电站事故后，人们越来越关注放射性致癌作用。此外，由于灾害而长期居住在避难所或临时住房中可能会导致不愉快的压力，从而对身心健康产生不利影响。实验已经证明，使用小鼠模型，“良性压力”（丰富和舒适的良性压力）对健康具有有益的影响。在之前的一项研究中，在丰富环境（EE）中饲养的小鼠显示出抑制肿瘤生长和增强癌症治疗期间药物敏感性的作用。但是，尚未评估 EE 是否会影响放射性致癌作用。因此，为了评估 EE 是否会抑制放射性暴露后引起的致癌作用，在这项研究中，我们使用小鼠模型评估了 EE 对血清瘦素水平、放射性诱导的 DNA 损伤反应和炎症反应的影响。简而言之，在操纵幼年或成年期饲养环境后，对接受辐射的小鼠进行了随时间采集血清和组织并进行分析。为了评估放射性诱导的 DNA 损伤反应，我们对作为 DNA 双链断裂标志物的磷酸化 H2AX 进行了免疫染色。我们专注于在致癌作用中起重要作用的炎症反应中巨噬细胞的极化，通过组织免疫荧光染色和 RT-qPCR 进行了分析。我们的数据证实，在辐射暴露之前进行 EE 繁殖可以提高对辐射诱导的 DNA 损伤和基础免疫的反应性，进一步抑制慢性炎症反应，从而可能降低放射性致癌作用的风险。
