Effect of low-dose ionizing radiation on oxidative stress and DNA damage repair in human lymphocytoid cells
OBJECTIVE:To investigate effect of low-dose 137Cs γ-irradiation on oxidative stress, DNA damage repair and indued DNA damage in normal human lymphocytoid cells (AHH-1). METHODS:AHH-1 cells were irradiated with 137Cs γ-rays at a dose rate of 8.32 mGy/min, with doses of 0 (unirradiated), 0.01, 0.02,0.05,0.075,0.1,and 0.2 Gy,and cultured for 1,24,48 and 72 h after irradiation,respectively. Cell viability was examined by a CCK-8 kits. The level of oxidative damage was detected by malondialdehyde (MDA), superoxide dismutase (SOD) and reactive oxygen species (ROS) kits. γH2AX and 53BP1 foci were performed by immunofluorescence. Changes in the expression levels of DNA damage repair-related genes CDKN1A, DDB2 and POLH mRNA were detected by real-time fluorescence quantitative PCR. RESULTS:Compared with the unirradiated group, cell viability were significantly increased at 24 and 48 h after irradiation (P<0.05). The differences in MDA levels and SOD activities were changed significantly in the 0.2 Gy (P<0.05);the relative fluorescence intensity of ROS was significantly increased in the doses of 0.02, 0.05, 0.075 Gy and 0.2 Gy at 48 h after irradiation. The number of γH2AX and 53BP1 focus increased with the doses, and there were good dose-response relationships at 1 h following radiation exposure (P<0.01). Compared with the unirradiated group,the relative mRNA expression level of DDB2 and POLH genes were significantly up-regulated at 48 h after irradiation (P<0.05). CONCLUSION:Exposure to low-doses of ionizing radiation induced changes in oxidative stress,DNA damage and expression of DNA damage repair-related genes in AHH-1 cells.
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维普
