Expression of DDB2, XPC, and GADD45 Genes after Whole Body Gamma Irradiation

The stimulation of DNA repair mechanisms is an immediate response to radiation-induced damage. Monitoring the expression of DNA-repair-related genes would be a beneficial method to identify bio-dosimeter of radiation exposure, particularly for challenging low-dose radiation. In this study, we aimed to evaluate the effect of different low doses of gamma radiation on the expression of DDB2, XPC, and GADD45A genes involved in DNA-damage repair mechanisms.

Forty-eight male rats were divided into a control group and five exposure groups. The latter groups exposed to various doses of γ-rays (Co-60) ranged from 20 mGy to 1000 mGy. 24 h after irradiation, isolated lymphocytes from collected blood samples were used for evaluating gene expression levels by real-time quantitative polymerase chain reaction (qRT-PCR). Data were expressed as means ± SD and were statistically evaluated using one‑way ANOVA or Kruskal-Wallis test. P value<0.05 was considered as a significant value.

DDB2, GADD45A, and XPC expression remained unchanged at a dose of 20 mGy, and at doses above 20 mGy, they changed significantly. XPC and GADD45A altered significantly at 50 mGy while DDB2 changed significantly after exposure to 100, 500, and 1000 mGy.

Low doses of gamma radiation (less than 1 Gy) can significantly affect DDB2, XPC, and GADD45A expression, three central genes in the DNA-damage repair process. The extent of the gene expression changes at higher doses of 100, 500, and 1000 mGy seems more severe than that of their lower counterparts (50 mGy).