应用形态学、琼脂糖凝胶电泳和流式细胞仪等方法观察ｒ射线诱导辐射敏感细胞ＨＬ－６０和辐射耐受细胞Ｋ５６２ 细胞凋亡和细胞周期改变的关系。结果：ＨＬ－６０细胞受照后出现Ｇ２期阻滞，１２ｈ达高峰，凋亡细胞比例随作用时间和 照射剂量的增加而增加，凋亡特有的梯状图谱分别在 １、５、１０Ｇｙ照后 ７２、２４、１２ｈ出现。 Ｋ５６２细胞受照后也出现 Ｇ２期阻滞，５、１０、２０Ｇｙ组分别在 ２４、４８、７２ｈ达高峰，未观察到细胞凋亡的发生。表明：细胞的辐射敏感性与致 凋亡的敏感性一致，辐射敏感细胞的凋亡与从Ｇ２期阻滞的退出有关。 Morphological, agarose gel electrophoresis and flow cytometry were used to observe the relationship between r-ray-induced apoptosis and cell cycle changes of the radiation-sensitive cell line HL-60 and the radiation-tolerant cell line K562. Results: G2-phase arrest occurred in HL-60 cells and peaked at 12h after irradiation. The proportion of apoptotic cells increased with the increase of irradiation time and dose, and the ladder-specific maps of apoptosis were at 1,5,10 Gy 72,24,12 h appear. There was G2 arrest in K562 cells after irradiation, and reached the peak at 24, 48 and 72 hours in 5, 10 and 20 Gy groups, respectively. No apoptosis was observed. The results showed that the radiosensitivity of the cells was consistent with the induction of apoptosis, and the apoptosis of the radiosensitive cells was related to the withdrawal from G2 arrest.