实验研究了低剂量γ射线预照射对人肝癌细胞系hepG2和人宫颈癌细胞系HeLa的细胞周期进程的影响.结果显示(1)低剂量(5cGy)辐射后,两种细胞的G2/M期细胞短暂累积;(2)低剂量辐射促进肿瘤细胞的生长;(3)高剂量(3Gy)辐射后,hepG2细胞发生G2期阻滞,HeLa细胞发生S期和G2期阻滞;(4)与单纯高剂量照射相比,低剂量辐射预处理后4h,再给予高剂量辐射,可进一步促进hepG2细胞在G2/M期累积,但是预照射对HeLa细胞的周期进程没有明显影响.因此,低剂量辐射预处理对高剂量诱导的细胞周期阻滞的影响依赖于肿瘤细胞的类型. The effects of low dose γ-ray pre-irradiation on the cell cycle progression of human hepatocarcinoma cell line hepG2 and human cervical cancer cell line HeLa were studied.The results showed that: (1) After low dose (5cGy) irradiation, G2 / M phase (2) Low dose radiation can promote the growth of tumor cells; (3) After high dose (3Gy) radiation, G2 phase arrest occurs in hepG2 cells and S phase and G2 phase arrest in HeLa cells; (4) Compared with the high-dose irradiation, the high-dose radiation 4 h after pretreatment with low-dose radiation could further promote the accumulation of hepG2 cells in G2 / M phase, however, pre-irradiation had no obvious effect on the cycle progression of HeLa cells. The effect of radiation preconditioning on high-dose-induced cell cycle arrest depends on the type of tumor cells.