Protective effect of CpG-oligodeoxynucleotides against low- and high-LET irradiation.
OBJECTIVE
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.
Section of Radiation Medicine, Department of Naval Medicine, Second Military Medical University, Shanghai, China.
Chao
C
Zhang
Min
M
Zheng
Xiang-Hui
XH
Zhu
Sha
S
Li
Jin
J
Ni
Bai-Long
BL
Li
Hu
H
Liu
Fu
F
Gao
Jian-Ming
JM
Cai
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000528:radiation effects; D059447:Cell Cycle Checkpoints / Q000187:drug effects / Q000528:radiation effects; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects* / Q000235:genetics / Q000528:radiation effects; D004249:DNA Damage / Q000187:drug effects* / Q000528:radiation effects; D059565:G2 Phase Cell Cycle Checkpoints / Q000187:drug effects / Q000528:radiation effects; D005720:Gamma Rays / Q000009:adverse effects*; D051379:Mice; D009838:Oligodeoxyribonucleotides / Q000494:pharmacology*; D020011:Protective Agents / Q000494:pharmacology*
C408982:CPG-oligonucleotide; D009838:Oligodeoxyribonucleotides; D020011:Protective Agents