低剂量照射对K562细胞凋亡、MMP及Caspase-3活性影响的实验研究  

The in Vitro Experimental Study of Influence on Change of MMP,Caspase-3 Activity and Apoptosis with Low Dose Radiation in Leukemia K562

作　　者：张海兵[1] 辛勇 章龙珍 

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

出　　处：《肿瘤学杂志》2015年第12期1004-1009,共6页Journal of Chinese Oncology

基　　金：国家自然科学资金项目(30770916)

摘　　要：[目的]探讨低剂量照射及低剂量联合大剂量照射对人红白血病细胞系K562凋亡、线粒体膜电位（MMP）变化及Caspase-3活性的影响及其可能机制。[方法]实验分成4组：对照组（0Gy）、低剂量照射组（0.08Gy、0.2Gy、0.5Gy、0.8Gy,LDR组）、大剂量照射组（6Gy,HDR组）及低剂量联合大剂量照射组（0.08Gy/6Gy、0.2Gy/6Gy、0.5Gy/6Gy、0.8Gy/6Gy,LDR/HDR组）,体外培养K562,取对数生长期细胞分瓶分组分别给予不同剂量的6MV-X射线照射;照射后按不同时间点收集细胞,流式细胞仪检测细胞凋亡及照射后24h细胞MMP（△Ψm）的变化,酶标仪检测照射后24h Caspase-3活性（A405nm OD值）变化。[结果]LDR后48h凋亡增加（P〈0.05）,96h达峰值（P〈0.01）,且随照射剂量增大而增加,0.5Gy及0.8Gy剂量组最高（P〈0.01）;LDR/HDR后24h凋亡增加（P〈0.05）,持续至96~120h达峰值（P〈0.01）,以0.5Gy/6Gy及0.8Gy/6Gy组凋亡最高,较对照组及HDR组比较差异均有统计学意义。LDR 24h后K562的△Ψm下降,LDR/HDR组△Ψm亦明显下降,以0.5Gy、0.8Gy、0.5Gy/6Gy及0.8Gy/6Gy组下降更明显（P〈0.05）。LDR 24h后Caspase-3活性增强（P〈0.05）;LDR/HDR 24h后,Caspase-3活性进一步增强（P〈0.05）。[结论]LDR能诱导K562凋亡,LDR有增强HDR对K562的凋亡作用;LDR后24h MMP下降及Caspase-3活性增强,且早于凋亡的增加,其可能机制为LDR增加K562细胞线粒体膜通透性,使MMP下降,Caspase-3活性增强,激活Caspase-3级联反应而启动线粒体凋亡途径。[Purpose] To investigate the effect on apoptosis,mitochondrial membrane potential change（MMP,△Ψm）and caspase-3 activaties by low dose irradiation or low dose irradiation combining high dose irradiation in human erythro-leukemia cell line K562 in vitro and the possible mechanisms. [Methods] The K562 cells in exponential growth phase were performed. The test was divided into four groups（ten subgroups）,including blank control group（0Gy,BC group）,low dose radiation group（LDR groups）,high dose radiation group（6Gy,HDR groups） and low dose radiation combining with high dose radiation group（LDR/HDR groups）.Cells were then radiation at room temperature with 6-MV X-ray by linear accelerator. After irradiation the each experimental group cells were incubated at 37℃ in humidified air 5% CO2 and then harvested for detection of cell apoptosis and mitochondrial membrane potential chang（MMP, △Ψm） in flow cytometer（FCM） after irradiation 24 h. Enzyme labeling instrument was used to measure the activity of caspase-3. [Results] The change in mitochondrial membrane potential（△Ψm） of the cells were decreased in all radiation groups.Moreover,the degree of breakdown in MMP had a relationship with the radiation doses.The change in MMP was also enhanced by the LDR combining HDR. The activity of caspase-3 was enhanced in all radiation groups.In the LDR combining HDR group,the activity of caspase-3 was higher than the HDR group and LDR group. [Conclusions] LDR may induce the K562 cells apoptosis and LDR may enhance HDR induced K562 apoptosis. The possible mechanism of LDR promote apoptosis effect in K562 including breakdown of MMP and enhancing the activity of caspase-3.

关 键 词：低剂量辐射 细胞凋亡 白血病/K562 线粒体膜电位 CASPASE-3 辐射超敏感性 

分 类 号：R73[医药卫生—肿瘤]