Objective This paper is to explore the DNA repair mechanism of immune adaptive response (AR) induced by low dose radiation (LDR),the changes of mRNA levels and protein expressions of p53,ATM,DNA-PK catalytic subunit (DNA-PKcs) and PARP-1 genes in the LDR-induced AR in EL-4 cells.Methods The apoptosis and cell cycle progression of EL-4 cells were detected by flow cytometry in 12 h after the cells received the pre-exposure of 0.075 Gy X-rays (inductive dose,D1) and the succeeding high dose irradiation (challenge dose,D2;1.0,1.5,and 2.0 Gy X-rays,respectively) with or without wortmannin (inhibitor of ATM and DNA-PK) and 3-aminobenzamid (inhibitor of PARP-1).And the protein expressions and mRNA levels related to these genes were detected with flow cytometry and reverse transcription-polymerase chain reaction in 12 h after irradiation with D2.Results The mRNA and protein expressions of p53 and PARP-1 in EL-4 cells in the D1 + D2 groups were much lower than those in the D2 groups,and those of PARP-1 in the 3-AB + D2 and the 3-AB + D1 + D2 groups were much lower than those in the D2 and the D1 + D2 groups.The percentage of apoptotic EL-4 cells in the 3-AB + D1 + D2 groups was much higher than that in the D1 + D2 groups,that in the G0/G1 and the G2+ M phases was much higher,and that in the S phase were much lower.Although the ATM and DNA-PKcs mRNA and protein expressions in wortmannin + D1 + D2 groups were much lower than those in the D1 + D2 groups,there were no significant changes in the apoptosis and cell cycle progression between the wortmannin + D1 + D2 and the D1 + D2 groups.Conclusion PARP-1 and p53 might play important roles in AR induced by LDR.
GUANG-HUI CHENGNING WUDE-Fu JIANGHONG-GUANG ZHAOQIAN ZHANGJIAN-FENG WANGSHou-LIANG GONG
