Novel Double-Hit Model of Radiation and Hyperoxia-Induced Oxidative Cell Damage Relevant to Space Travel.
Novel Double-Hit Model of Radiation and Hyperoxia-Induced Oxidative Cell Damage Relevant to Space Travel.
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DOI：
10.3390/ijms17060953
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发表时间：
2016-06-16
影响因子：
5.6
通讯作者：
Christofidou-Solomidou M
中科院分区：
文献类型：
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作者：
Pietrofesa RA;Velalopoulou A;Lehman SL;Arguiri E;Solomides P;Koch CJ;Mishra OP;Koumenis C;Goodwin TJ;Christofidou-Solomidou M
航天飞行有时需要多次舱外活动（EVA），这些活动可能使宇航员受到环境氧气的反复变化和空间辐射暴露的叠加。因此，我们开发了一种新的体外模型系统来测试反复暴露于辐射和高氧后的肺细胞损伤。非致瘤性小鼠肺泡II型上皮细胞（C10）仅暴露于>95% O2 (O2) 8小时，仅暴露于0.25 Gy电离γ辐射（IR），或两种挑战的双重组合（O2 + IR），然后暴露于16小时的常氧环境（环境空气中含有21%的O2和5%的CO2）（1周期= 24小时，2周期= 48小时）。在1和2个暴露周期后评估细胞存活、DNA损伤、凋亡和氧化应激指标。我们观察到，与未暴露于高氧或辐射的细胞相比，在所有刺激条件下，细胞存活率显著（p < 0.05）下降，DNA损伤（通过Comet分析和H2AX磷酸化测定）增加，凋亡（通过Annexin-V染色测定）增加。DNA损伤（GADD45α和cleaved- parp）、凋亡（cleaved caspase-3和BAX）和抗氧化（HO-1和Nqo1）蛋白在辐射和高氧暴露1和2个周期后增加。重要的是，与单独暴露于O2或IR相比，暴露于O2 + IR联合挑战加重了细胞死亡和DNA损伤。此外，所有暴露组的细胞周期蛋白磷酸化p53和p21水平均显著升高，而CDK1和Cyclin B1水平在两个时间点均下降。同样，与单独的压力源相比，在组合挑战下，参与细胞周期阻滞的蛋白质发生了更深刻的变化。这些结果与暴露于高氧条件2个周期后G2/G1细胞比例显著增加4至6倍相关。我们描述了一种新的体外模型，双重打击，低水平辐射和高氧暴露导致氧化性肺细胞损伤，DNA损伤，细胞凋亡和细胞周期阻滞。
Spaceflight occasionally requires multiple extravehicular activities (EVA) that potentially subject astronauts to repeated changes in ambient oxygen superimposed on those of space radiation exposure. We thus developed a novel in vitro model system to test lung cell damage following repeated exposure to radiation and hyperoxia. Non-tumorigenic murine alveolar type II epithelial cells (C10) were exposed to >95% O2 for 8 h only (O2), 0.25 Gy ionizing γ-radiation (IR) only, or a double-hit combination of both challenges (O2 + IR) followed by 16 h of normoxia (ambient air containing 21% O2 and 5% CO2) (1 cycle = 24 h, 2 cycles = 48 h). Cell survival, DNA damage, apoptosis, and indicators of oxidative stress were evaluated after 1 and 2 cycles of exposure. We observed a significant (p < 0.05) decrease in cell survival across all challenge conditions along with an increase in DNA damage, determined by Comet analysis and H2AX phosphorylation, and apoptosis, determined by Annexin-V staining, relative to cells unexposed to hyperoxia or radiation. DNA damage (GADD45α and cleaved-PARP), apoptotic (cleaved caspase-3 and BAX), and antioxidant (HO-1 and Nqo1) proteins were increased following radiation and hyperoxia exposure after 1 and 2 cycles of exposure. Importantly, exposure to combination challenge O2 + IR exacerbated cell death and DNA damage compared to individual exposures O2 or IR alone. Additionally levels of cell cycle proteins phospho-p53 and p21 were significantly increased, while levels of CDK1 and Cyclin B1 were decreased at both time points for all exposure groups. Similarly, proteins involved in cell cycle arrest was more profoundly changed with the combination challenges as compared to each stressor alone. These results correlate with a significant 4- to 6-fold increase in the ratio of cells in G2/G1 after 2 cycles of exposure to hyperoxic conditions. We have characterized a novel in vitro model of double-hit, low-level radiation and hyperoxia exposure that leads to oxidative lung cell injury, DNA damage, apoptosis, and cell cycle arrest.