低剂量X射线照射对K562细胞周期及凋亡影响的实验研究  

Influence on proliferation and apoptosis with low dose irradiation in leukemia K562 in vitro

作　　者：张海兵[1] 辛勇 黄倩 郭雯雯 章龙珍 

机构地区：[1]湖州市中心医院放疗科,浙江湖州313000 [2]徐州医科大学附属医院放疗科,江苏徐州221002

出　　处：《中华肿瘤防治杂志》2016年第7期420-425,430,共7页Chinese Journal of Cancer Prevention and Treatment

基　　金：国家自然科学基金(30770916);江苏省自然基金(BK20131131)

摘　　要：目的低剂量照射(low-dose radiation,LDR)可调节细胞信号传导,通过各种基因和蛋白的表达改变其分子生物学效应,由此产生了多样复杂且不同于大剂量照射的生物效应。用LDR及LDR联合大剂量照射(high-dose radiation,HDR)人红白血病细胞系K562(CML),探讨LDR对K562细胞周期进程及凋亡的影响。方法按照K562细胞照射剂量不同分为4组,对照组(0Gy)、LDR组(0.08、0.50Gy)、HDR组(6Gy)及LDR联合HDR组(0.08/6Gy、0.50/6Gy,LDR/HDR组)。采用6 MV X射线照射,LDR与HDR间隔8h;照射后按不同时间点收集细胞,流式细胞仪检测细胞周期变化与凋亡并分析细胞DNA倍体变化。结果 LDR后6h各组S期比例增加,对照组与LDR各组分别为55.38±2.22 vs 71.91±7.30、73.13±4.09(Z=-2.428,P=0.022;Z=-3.987,P<0.001);12hG2/M期细胞比例增加,出现G2/M阻滞,24h达峰值,对照组与LDR各组分别为17.81±1.27 vs 26.61±7.82、29.02±2.76(Z=-3.684,P<0.001;Z=-2.928,P<0.001);48h各组G0/G1细胞增多,72h达峰值,对照组与LDR各组分别为27.07±1.19 vs52.32±2.42、44.06±1.90(Z=-2.351,P=0.020;Z=-2.172,P=0.032)。LDR/HDR后6hS期细胞比例增多,且G2/M期比例增加,即G2/M期阻滞,12h达峰值并持续至24h,12h HDR组与LDR/HDR各组G2/M期分别为26.98±2.15 vs 56.27±1.57、69.31±2.51(Z=-2.564,P=0.021;Z=-7.759,P<0.001)。LDR后48h凋亡率增加,96h达峰值,对照组与LDR各组分别为1.82±0.12 vs 3.21±0.20、6.28±0.30(Z=-3.959,P=0.003;Z=-9.705,P<0.001);LDR/HDR照射后24h凋亡率增加,120h达峰值,HDR组与LDR/HDR各组分别为14.21±0.61 vs 17.38±0.92、27.91±1.07(Z=-2.986,P=0.027;Z=-6.973,P<0.001)。LDR后6h各组四倍体及八倍体细胞增加,且随照射剂量增大而增多,对照组与LDR各组八倍体细胞分别为2.41±0.15 vs 4.84±0.46、7.83±0.59,差异有统计学意义,H值分别为5.956和7.200,P值分别为0.025和0.001;LDR/HDR后6h各组四倍体及八倍体细胞增加,亦随LDR剂量增大而增多,HDR组与LDR/HDR各组八倍体细胞分别为6.49±1.05 vs 10.8OBJECTIVE Low dose irradiation （LDR） can regulate cell signaling by altering the expression of genes and proteins and produce various and complicated biological effects different from high-dose radiation（HDR）. The study was to investigate the effect on cell cycle and apoptosis by LDR or LDR/HDR in human erythro-leukemia cell line K562 in vitro. METHODS The test were divided into four groups（six subgroups）, including hlank control group（0 Gy, BC）, LDR group（0.08 Gy, 0.50 Gy）, HDR group（6 Gy） and LDR/HDR group（0.08/6 Gy, 0.50/6 Gy）. Then cells were radiated at room temperature with 6-MV X-ray by linear accelerator. Flow cytometry（FCM） was used to analyze the cell cycle uncoupling, apoptosis and polyploid after irradiation. RESULTS The number of cell cycle S phase cells were more significantly increased in the LDR group after 6 hours than that in BC group（55. 38 ±2.22 vs 71. 91±7.30, 73. 13 ± 4.09） （Z=-2. 428, P=0.022; Z=-3.987, P〈0.001）. The percentage of cell cycle G2/M phase arrest after LDR 6 hours had no change, at 12 to 24 hours it increased significantly. The BC group versus the LDR group was 17.81± 1.27 vs 26.61±7.82, 29.02±2.76 respctively（Z=-3.684, P〈0.001; Z=-2.928, P〈0.001）. The percentage of G2/M phase cells arrest after LDR combining HDR 6 hours increased continuously to the peak at 24 hours. The number of G0/G1 phase cells in LDR group increased at 48 h and reached the peak at 72 h expressed as 52.32± 2.42, 44.06± 1.90 respectively, with statistically significant differences compared with those of 27.07±1.19（BC group）（Z=-2. 351, P=0. 020;Z=-2. 172,P=0. 032）. The number of S phase cells were more significantly increased to the peak in the LDR/HDR group than that of BC group after LDR/HDR 6 h,12 h to 24 h decreased significantly to the minimum. The G2/M phase at 12 h in HDR group versus LDR/HDR group was 26. 98±2. 15 vs 56. 27±1. 57, 69. 31±2. 51（Z= -2. 564, P〈0. 021; Z=-7. 759, P〈0. 001） with statistically significant differe

关 键 词：低剂量辐射 白血病/K562 凋亡 细胞周期解偶联 多倍体细胞 

分 类 号：R730.5[医药卫生—肿瘤]