Zhang Chao, Zheng Min, Zhu Xiang-Hui, Li Sha, Ni Jin, Li Bai-Long, Liu Hu, Gao Fu, Cai Jian-Ming
Section of Radiation Medicine, Department of Naval Medicine, Second Military Medical University, Shanghai, China.
Cell Physiol Biochem. 2014;34(5):1663-74. doi: 10.1159/000366368. Epub 2014 Nov 5.
BACKGROUND/AIMS: CpG-oligodeoxynucleotides (ODNs) are synthetic DNA sequences containing unmethylated cytosine-guanine motifs with potent immunomodulatory effects. Previous reports showed a powerful protective effect of CpG-ODN against the damage induced by low-LET γ-rays. In this study, we explored whether CpG-ODN also protects against the damage induced by high-LET irradiation. Parallel experiments were performed with low-LET irradiation.
RAW264.7 cells were incubated with 1 μM of CpG-ODN after γ-ray or carbon-beam irradiation. Cell death was then measured by PI/DAPI double staining, cell survival was assessed by colony-formation assays, DNA damage was evaluated by comet assays, cell cycle was monitored by flow cytometry, and the levels of apoptosis-related proteins were detected by western blots.
When irradiated cells were treated with the CpG-ODN, cell viability decreased, cell survival increased, DNA damage and G2/M-phase arrest were ameliorated, and apoptosis was inhibited.
The CpG-ODN showed protective effects against low-LET γ-ray and high-LET carbon-beam irradiation. These effects might be associated with the repair of DNA damage and inhibition of apoptosis.
背景/目的：CpG寡脱氧核苷酸（ODNs）是含有未甲基化胞嘧啶-鸟嘌呤基序的合成DNA序列，具有强大的免疫调节作用。先前的报告显示CpG-ODN对低线性能量传递（LET）γ射线诱导的损伤具有强大的保护作用。在本研究中，我们探讨了CpG-ODN是否也能保护免受高线性能量传递辐射诱导的损伤。同时进行了低线性能量传递辐射的平行实验。
RAW264.7细胞在γ射线或碳束照射后与1μM CpG-ODN孵育。然后通过PI/DAPI双重染色测量细胞死亡，通过集落形成试验评估细胞存活，通过彗星试验评估DNA损伤，通过流式细胞术监测细胞周期，并通过蛋白质印迹检测凋亡相关蛋白的水平。
当用CpG-ODN处理受照射细胞时，细胞活力降低，细胞存活增加，DNA损伤和G2/M期阻滞得到改善，凋亡受到抑制。
CpG-ODN对低线性能量传递γ射线和高线性能量传递碳束照射均显示出保护作用。这些作用可能与DNA损伤修复和凋亡抑制有关。
