Time-Dependent Induction of the Nucleotide Excision Repair Gene XPA and RAD51 in Homologous Recombination in Human Lymphocytes Exposed to Low Doses of Ionizing Radiation

Document Type : Original Paper


1 Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.

2 Department of Radiology Technology, School of Paramedical Sciences, Mashhad University of Medical Sciences, Mashhad, Iran

3 Medical Physics Research Center, Mashhad University of Medical Sciences, Mashhad, Iran


Introduction: The aim of the present study was to understand the effect of low-doses of ionizing radiation (LDIR) on repair genes expression in blood samples that were taken from healthy donors. The next purpose was to examine the time-effect on the modified gene expression caused by low-doses of ionizing radiation.
Material and method: The RNA of peripheral blood lymphocytes (PBLs) taken from four healthy donors was isolated at different time points after exposure included 4, 24, 48, 72, and 168 hours and then cDNA was synthesized. Modification of XPA and RAD51 expression levels due to LDIR (2, 5, 10 cGy) were evaluated by relative quantitative reverse transcription-polymerase chain reaction.
Results: Significant up-regulation of both repair genes was observed at the 4 and 168 h following to 10 cGy. Also, this dose could increase expression levels of RAD51 at 48 and 72 h after radiation. For lower doses at 5 cGy, only XPA levels were significantly up-regulated after 168 h. A significant regression was found between the XPA levels and the dose, at 168 h after irradiation to PBLs that can represent a new potential biomarker for biological dosimetry purposes.
Conclusion: The results of this study could support the hypothetical role of the different DNA repair pathways in response to LDIR. This led us to propose a molecular biodosimetry method for ionizing radiation in the range of LDIR.


Main Subjects

Articles in Press, Accepted Manuscript
Available Online from 23 February 2021
  • Receive Date: 21 November 2020
  • Revise Date: 18 February 2021
  • Accept Date: 23 February 2021