Kataoka Takahiro, Etani Reo, Kanzaki Norie, Kobashi Yusuke, Yunoki Yuto, Ishida Tsuyoshi, Sakoda Akihiro, Ishimori Yuu, Yamaoka Kiyonori
Graduate School of Health Sciences, Okayama University, 5-1 Shikata-cho, 2-chome, Kita-ku, Okayama 700-8558, Japan.
Oita University of Nursing and Health Sciences, 2944-9 Megusuno, Oita City, Oita 870-1201 Japan.
J Radiat Res. 2017 Nov 1;58(6):887-893. doi: 10.1093/jrr/rrx048.
Although radon inhalation increases superoxide dismutase (SOD) activities in mouse organs, the mechanisms and pathways have not yet been fully clarified. The aim of this study was to determine the details of SOD activation in mouse brain tissue following the inhalation of radon at concentrations of 500 or 2000 Bq/m3 for 24 h. After inhalation, brains were removed quickly for analysis. Radon inhalation increased the manganese (Mn)-SOD level and mitochondrial SOD activity. However, the differences were not significant. There were no changes in the Cu/Zn-SOD level or cytosolic SOD activity. Radon inhalation increased the brain nuclear factor (NF)-κB content, which regulates the induction of Mn-SOD, in the nuclear and cytosolic compartments. The level of inhibitor of nuclear factor κB kinase subunit β (IKK-β), which activates NF-κB, was slightly increased by radon inhalation. The expression of cytoplasmic ataxia-telangiectasia mutated kinase in mice inhaling radon at 500 Bq/m3 was 50% higher than in control mice. In addition, NF-κB-inducing kinase was slightly increased after inhaling radon at 2000 Bq/m3. These findings suggest that radon inhalation might induce Mn-SOD protein via NF-κB activation that occurs in response to DNA damage and oxidative stress.
尽管吸入氡会增加小鼠器官中超氧化物歧化酶（SOD）的活性，但其机制和途径尚未完全阐明。本研究的目的是确定在浓度为500或2000 Bq/m³的氡气中吸入24小时后，小鼠脑组织中SOD激活的详细情况。吸入后，迅速取出大脑进行分析。吸入氡气会增加锰（Mn）-SOD水平和线粒体SOD活性。然而，差异并不显著。铜/锌-SOD水平或胞质SOD活性没有变化。吸入氡气会增加细胞核和细胞质中调节Mn-SOD诱导的脑核因子（NF）-κB含量。激活NF-κB的核因子κB激酶亚基β（IKK-β）的水平因吸入氡气而略有增加。吸入500 Bq/m³氡气的小鼠中细胞质共济失调毛细血管扩张突变激酶的表达比对照小鼠高50%。此外，吸入2000 Bq/m³氡气后，NF-κB诱导激酶略有增加。这些发现表明，吸入氡气可能通过响应DNA损伤和氧化应激而发生的NF-κB激活来诱导Mn-SOD蛋白。
