In vitro and in vivo studies on radiobiological effects of prolonged fraction delivery time in A549 cells
In vitro and in vivo studies on radiobiological effects of prolonged fraction delivery time in A549 cells
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DOI：
10.1093/jrr/rrs093
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发表时间：
2013-03-01
影响因子：
2
通讯作者：
Ying, Hong-Mei
中科院分区：
文献类型：
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作者：
Jiang, Ling;Xiong, Xiao-Peng;Ying, Hong-Mei
调强放射治疗在临床上使用时，延长了部分给药时间。在此，我们研究了A549细胞的体内和体外放射生物学效应，包括相同剂量不同给药时间对A549裸鼠肿瘤生长的影响。用克隆形成法研究体外效应，用线性-二次和不完全修复模型拟合剂量-存活曲线。不同剂量的分次照射，每天一次，模拟临床剂量-时间-分次模式。暴露之间的间隔越长，存活的细胞越多。为了研究A549细胞的体内效应，我们用64只裸鼠后腿移植A549细胞，随机分为8组。15Gy射线照射剂量分为不同的亚组分。记录肿瘤的最大直径和最小直径以确定肿瘤的生长情况。与单次15Gy组相比，肿瘤生长延迟[20‘(7.5Gyx2F)vs40’(7.5Gyx2F)，P=0.035；20‘(3Gyx5F)vs40’(3Gyx5F)；P=0.054；20‘(1.67Gyx9F)vs40’(1.67Gyx9F)，P=0.028]。延长分娩时间会降低放射生物学效应，因此我们强烈建议尽量缩短分娩时间。
Intensity-modulated radiation therapy, when used in the clinic, prolongs fraction delivery time. Here we investigated both the in vivoand in vitroradiobiological effects on the A549 cell line, including the effect of different delivery times with the same dose on A549 tumor growth in nude mice. The in vitroeffects were studied with clonogenic assays, using linear-quadratic and incomplete repair models to fit the dose-survival curves. Fractionated irradiation of different doses was given at one fraction per day, simulating a clinical dose-time-fractionation pattern. The longer the interval between the exposures, the more cells survived. To investigate the in vivoeffect, we used sixty-four nude mice implanted with A549 cells in the back legs, randomly assigned into eight groups. A 15 Gy radiation dose was divided into different subfractions. The maximum and minimum tumor diameters were recorded to determine tumor growth. Tumor growth was delayed for groups with prolonged delivery time (40 min) compared to the group receiving a single dose of 15 Gy (P < 0.05), and tumors with a 20 min delivery time had delayed growth compared to those with a 40 min delivery time [20' (7.5 Gy x 2 F) vs 40' (7.5 Gy x 2 F), P= 0.035; 20' (3 Gy x 5 F) vs 40' (3 Gy x 5 F); P= 0.054; 20' (1.67 Gy x 9 F) vs 40' (1.67 Gy x 9 F), P= 0.028]. A prolonged delivery time decreased the radiobiological effects, so we strongly recommend keeping the delivery time as short as possible.