Geraldo Jony M, Scalzo Sérgio, Reis Daniela S, Leão Thiago L, Guatimosim Silvia, Ladeira Luiz O, Andrade Lídia M
a Departamento de Anatomia por Imagens , Universidade Federal de Minas Gerais , Belo Horizonte , Brazil.
b Centro de Desenvolvimento da Tecnologia Nuclear , Belo Horizonte , Brazil.
Int J Radiat Biol. 2017 Sep;93(9):958-966. doi: 10.1080/09553002.2017.1341661. Epub 2017 Jul 4.
To investigate the effects of high dose rate (HDR) brachytherapy on cellular progression of a radioresistant human squamous cell carcinoma in vitro, based on clinical parameters.
An acrylic platform was designed to attach tissue culture flasks and assure source positioning during irradiation. At exponential phase, A431cells, a human squamous cell carcinoma, were irradiated twice up to 1100 cGy. Cellular proliferation was assessed by Trypan blue exclusion assay and survival fraction was calculated by clonogenic assay. DNA content analysis and cell cycle phases were assessed by flow cytometry and gel electrophoresis, respectively. Cellular death patterns were measured by HOPI double-staining method.
Significant decreasing cellular proliferation rate (p < 0.05) as well as reduced survival fraction (p < 0.001) in irradiated cells were observed. Moreover, increased percentage of cells arrested in the G/M phase (32.3 ± 1.5%) in the irradiated group as compared with untreated cells (8.22 ± 1.2%) was detected. Also, a significant (p < 0.0001) nuclei shrinking in irradiated cells without evidence of necrosis or apoptosis was found.
HDR brachytherapy led to a decreased proliferation rate and cell survival and also hampered cellular progression to mitosis suggesting that tumor cell death mainly occurred due to mitotic death and G/M cell cycle arrest.
基于临床参数，研究高剂量率（HDR）近距离放射治疗对体外耐辐射人鳞状细胞癌细胞进程的影响。
设计一个丙烯酸平台，用于连接组织培养瓶并确保照射期间源的定位。在指数生长期，对人鳞状细胞癌A431细胞进行两次照射，剂量高达1100 cGy。通过台盼蓝排斥试验评估细胞增殖，通过克隆形成试验计算存活分数。分别通过流式细胞术和凝胶电泳评估DNA含量分析和细胞周期阶段。通过HOPI双重染色法测量细胞死亡模式。
观察到照射细胞的细胞增殖率显著降低（p < 0.05）以及存活分数降低（p < 0.001）。此外，检测到照射组中停滞在G/M期的细胞百分比增加（32.3 ± 1.5%），而未处理细胞为（8.22 ± 1.2%）。同时，发现照射细胞中细胞核显著缩小（p < 0.0001），且无坏死或凋亡迹象。
HDR近距离放射治疗导致增殖率和细胞存活率降低，也阻碍细胞向有丝分裂进程，提示肿瘤细胞死亡主要是由于有丝分裂死亡和G/M期细胞周期停滞。
