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Updated: Apr 20, 2026

Application of Laser Micro-irradiation for Examination of Single and Double Strand Break Repair in Mammalian Cells
Published on: September 5, 2017
Protective effect of CpG-oligodeoxynucleotides against low- and high-LET irradiation
Chao Zhang1, Min Zheng, Xiang-Hui Zhu
1Section of Radiation Medicine, Department of Naval Medicine, Second Military Medical University, Shanghai, China.
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.
Methods:
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.
Results:
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.
Conclusions:
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.
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