Expression of DDB۲, XPC, and GADD۴۵ Genes after Whole Body Gamma Irradiation

Introduction: 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 DDB۲, XPC, and GADD۴۵A genes involved in DNA-damage repair mechanisms.Material and Methods: 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-۶۰) ranged from ۲۰ mGy to ۱۰۰۰ mGy. ۲۴ 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<۰.۰۵ was considered as a significant value.Results: DDB۲, GADD۴۵A, and XPC expression remained unchanged at a dose of ۲۰ mGy, and at doses above ۲۰ mGy, they changed significantly. XPC and GADD۴۵A altered significantly at ۵۰ mGy while DDB۲ changed significantly after exposure to ۱۰۰, ۵۰۰, and ۱۰۰۰ mGy.Conclusion: Low doses of gamma radiation (less than ۱ Gy) can significantly affect DDB۲, XPC, and GADD۴۵A expression, three central genes in the DNA-damage repair process. The extent of the gene expression changes at higher doses of ۱۰۰, ۵۰۰, and ۱۰۰۰ mGy seems more severe than that of their lower counterparts (۵۰ mGy).

Keywords:

Gamma Radiation , Rats , Gene expression , Lymphocytes , DNA damage