Ningyo-Toge Environmental Engineering Center, Japan Atomic Energy Agency, 1550 Kamisaibara, Kagamino-cho, Tomata-gun, Okayama 708-0698, Japan.
Faculty of Health Sciences, Okayama University, 5-1 Shikata-cho 2-chome, Kita-ku, Okayama 700-8558, Japan.
Int J Environ Res Public Health. 2022 Aug 29;19(17):10750. doi: 10.3390/ijerph191710750.
Therapy using hot springs, including the high-level radioactive gas "radon", is traditionally conducted as an alternative treatment for various diseases. Oxidative-stress-related diseases are inhibited by the enhancement of antioxidative functions following radon inhalation. We have reported that radon inhalation increased the level of anti-oxidants, such as glutathione (G-SH), in the brain and had a protective antioxidative effect against transient global cerebral ischemic injury. However, no studies have yet revealed the changes in G-SH associated substances after radon inhalation. In this study, we comprehensively analyzed several metabolites, focusing on G-SH. Mice were exposed to radon at concentrations of 200, 2000, or 20,000 Bq/m for 1, 3, or 10 days. We detected 27 metabolites in the mouse brains. The result showed that the L-methionine levels increased, whereas the levels of urea, glutathione, and sulfite ion decreased under any condition. Although the ratio of G-SH to oxidized glutathione (GS-SG) decreased, glutathione monosulfide (G-S-SH) and cysteine monosulfide (Cys-S-SH) increased after radon inhalation. G-S-SH and Cys-S-SH can produce a biological defense against the imbalance of the redox state at very low-dose irradiation following radon inhalation because they are strong scavengers of reactive oxygen species. Additionally, we performed an overall assessment of high-dimensional data and showed some specific characteristics. We showed the changes in metabolites after radon inhalation using partial least squares-discriminant analysis and self-organizing maps. The results showed the health effects of radon, especially the state of sulfur-related metabolites in mouse brains under the exposure conditions for radon therapy.
温泉疗法，包括高水平放射性气体“氡”，传统上被用作治疗各种疾病的替代疗法。氡吸入后增强抗氧化功能，抑制氧化应激相关疾病。我们曾报道，氡吸入会增加大脑中的抗氧化剂水平，如谷胱甘肽（G-SH），并对短暂性全脑缺血损伤具有保护抗氧化作用。然而，目前尚无研究揭示氡吸入后 G-SH 相关物质的变化。在这项研究中，我们综合分析了几种代谢物，重点是 G-SH。将小鼠暴露于浓度为 200、2000 或 20000 Bq/m 的氡中 1、3 或 10 天。我们在小鼠大脑中检测到 27 种代谢物。结果表明，L-蛋氨酸水平升高，而在任何条件下，尿素、谷胱甘肽和亚硫酸根离子水平降低。尽管 G-SH 与氧化型谷胱甘肽（GS-SG）的比值降低，但氡吸入后 G-S-SH 和半胱氨酸单硫醚（Cys-S-SH）增加。G-S-SH 和 Cys-S-SH 可以在氡吸入后产生非常低剂量照射下氧化还原状态失衡的生物防御，因为它们是活性氧的强清除剂。此外，我们对高维数据进行了全面评估，并显示了一些特定特征。我们使用偏最小二乘判别分析和自组织映射显示了氡吸入后代谢物的变化。结果表明了氡的健康效应，特别是在氡治疗暴露条件下，小鼠大脑中与硫相关代谢物的状态。
