CAJ | 학술논문

目的探讨延长时间的调强照射对鼻咽低分化鳞癌细胞系(CNE-2)放射生物效应的影响以及初步机制研究.方法实验分为空白对照组、单次照射组、模拟调强照射组,照射采用6 MVX线照射2、4、6、8 Gy(成克隆实验增加1 Gy剂量点),剂量率3 Gy/min.单次照射组完成时间1～3min,模拟调强照射组各剂量点分别等分割5次,每次间隔8.0～8.5 min.采用克隆分析法检测不同照射模式下CNE-2细胞的放射敏感性;流式细胞仪检测细胞凋亡率;RT-PCR法检测细胞凋亡相关因子Bax、Bcl-2的转录水平.结果模拟调强照射组不同剂量的存活分数均高于单次照射组,其α单次照射>α模拟调强照射(0.675 Gy-1:0.538 Gy-1)、β单次照射>β模拟调强照射(0.051 Gy-2:0.027 Gy-2)、D0单次照射<D0模拟谓强照射(0.885 Gy:0.986 Gy)、Dq单次照射<Dq模拟调强照射(0.563 Gy:0.946 Gy).模拟调强照射组CNE-2细胞早、晚期平均凋亡率均低于单次照射组[21.20%:15.89%(F=18.51,P=0.020)、13.00%:10.20%(F=15.67,P=0.040)].模拟调强照射组Bax平均转录水平低于单次照射组[76.75%:62.50%(F=36.57,P=0.000)]并呈剂量依赖件关系;Bcl-2平均转录水平两组差异无统计学意义[29.25%:29.75%(F=0.74,P=0.800)];Bax/Bcl-2比平均值模拟调强照射组低于单次照射组[26.50%:21.10%(F=16.02,P=0.020)].结论模拟调强照射模式下随分次照射时间延长,相对剂量率降低,从而导致生物效应下降.
목적 탐토연장시간적조강조사대비인저분화린암세포계(CNE-2)방사생물효응적영향이급초보궤제연구.방법 실험분위공백대조조、단차조사조、모의조강조사조,조사채용6 MVX선조사2、4、6、8 Gy(성극륭실험증가1 Gy제량점),제량솔3 Gy/min.단차조사조완성시간1～3min,모의조강조사조각제량점분별등분할5차,매차간격8.0～8.5 min.채용극륭분석법검측불동조사모식하CNE-2세포적방사민감성;류식세포의검측세포조망솔;RT-PCR법검측세포조망상관인자Bax、Bcl-2적전록수평.결과 모의조강조사조불동제량적존활분수균고우단차조사조,기α단차조사>α모의조강조사(0.675 Gy-1:0.538 Gy-1)、β단차조사>β모의조강조사(0.051 Gy-2:0.027 Gy-2)、D0단차조사<D0모의위강조사(0.885 Gy:0.986 Gy)、Dq단차조사<Dq모의조강조사(0.563 Gy:0.946 Gy).모의조강조사조CNE-2세포조、만기평균조망솔균저우단차조사조[21.20%:15.89%(F=18.51,P=0.020)、13.00%:10.20%(F=15.67,P=0.040)].모의조강조사조Bax평균전록수평저우단차조사조[76.75%:62.50%(F=36.57,P=0.000)]병정제량의뢰건관계;Bcl-2평균전록수평량조차이무통계학의의[29.25%:29.75%(F=0.74,P=0.800)];Bax/Bcl-2비평균치모의조강조사조저우단차조사조[26.50%:21.10%(F=16.02,P=0.020)].결론 모의조강조사모식하수분차조사시간연장,상대제량솔강저,종이도치생물효응하강.
Objective To study the altered radiobiological effect of simulative intensity-modulated radiotherapy (SIMR) in cultured human nasopharyngeal carcinoma (NPC) cells and the related mechanism. Methods Single cell suspension of exponentially growing CNE-2 cells, a poor differentiated NPC cell line, was seeded and cultured for 12 hours, then the cells were irradiated in two different models by 6 MV X-ray beams at 3 Gy/min. In single fraction irradiation (SFR) model, cells were irradiated a single fraction of 0, 2, 4, 6 or 8 Gy within 0 to 3 minutes. In S1MR model, cells were irradiated 0, 2, 4, 6 or 8 Gy in 5 frac-tions with interval of 8.0-8.5 minutes between. Clonogenic assay was performed to determine the radiosen-sitivity. Cellular apoptosis was measured by flow cytometry. RT-PCR was used to detect mRNA expressions of Bax and Bcl-2, Respectively. Results Compared with SFR group, the survival fraction in SIMR group was higher at all the dose levels. The values of α, β, D0 and Dq were higher in SIMR group than in SFR group. At dose levels of 2 Gy, 4 Gy and 6 Gy, The early and late apoptotic cells in SIMR group were lower than in SFR group (21.20%: 15.89%, F=18.51, P=0.020;13.00%: 10.20, F=15.67, P=0.040).The mRNA expression of Bax was upregulated in a dose-dependent manner in the both groups. Compared with SFR group, the mRNA expression of Bax in SIMR group was lower at all the dose levels (Mean value of 76.75% : 62.50%, F =36.57, P =0.000). Bcl-2 mRNA expression at every dose level had no significant difference between the two groups (Mean value of 29.25% : 29.75%, F=0.74, P=0.800). Conclusions Prolonged delivery time in SIMR model can decrease the radiobiological effects.