Abstract: Objective To study the methylation changes in promoter CpG islands induced by low-dose X-ray radiation (LDR).
Methods Twenty male BALB/c mice were randomly divided into control and fractionated radiation group exposed to 6 MV
X-ray for 10 days (0.05 Gy/day). All the mice were sacrificed 2 h after the last radiation on day 10, and blood samples were
collected for detecting DNA methylation changes using Roche-NimbleGen mouse DNA methylation 3 × 720K Promoter Plus
CpG Island Array. MeDIP-qPCR was used to further validate the methylation status of specific genes. Results A total of 811
genes were found to show specific hypermethylation in fractional radiation group as compared with the control group,
involving almost all the main biological processes by GO analysis. Eight candidate genes (Rad23b, Tdg, Ccnd1, Ddit3, Llgl1,
Rasl11a, Tbx2, and Slc6a15) were confirmed to be hypermethylated in LDR samples by MeDIP-qPCR, consistent with the
results of the methylation chip study. Conclusion LDR induces promoter hypermethylation on specific genes, which may
contribute to radiation-induced pathogenesis.