放射性^(125)I粒子照射小鼠膀胱癌模型的实验研究

Experimental research of interstitial implantation of ^(125)I seeds to treat bladder cancer in mice

目的:揭示125I粒子照射膀胱癌的生物学效应,为临床应用125I粒子治疗膀胱癌提供实验依据.方法:把T739近交系小鼠膀胱低分化移行细胞癌动物8只随机分为两组,实验组和对照组,每组4只.在小鼠瘤体内植入MSI-125型125I粒子,在对照组小鼠瘤体内相应部位植入粒子空壳,继续饲养24d后处死.在距粒子植入部位0.6,1.2,1.8cm的小鼠肿瘤内分别取3块组织,分离后行癌细胞培养,显微镜下动态观察细胞病理形态变化及生长、增殖状况.统计克隆形成率,计算克隆形成抑制率.结果:①实验组细胞数量明显少于对照组.实验组不同部位的培养细胞数量有较明显差异.②实验组克隆形成抑制率为41.84%.③两组不同部位所取组织细胞的总体克隆形成率有显著差异(P<0.01),实验组不同部位间亦有显著差异(P<0.01).结论:植入的125I粒子主要是靠γ射线的穿透力在有效射程内直接杀伤癌细胞,随着距离延长,辐射剂量减少,γ射线对癌细胞杀伤作用下降.

AIM： To get insights into the biological effect of implanting ^125Ⅰ seeds to treat bladder cancer model of T139 mice and to provide an experimental basis for clinical utilization of ^125Ⅰ seed brachytherapy for bladder cancer. METHODS： Eight mice models bearing T139 bladder cancer were divided into 2 groups （experimental, 4; control, 4） at random. ^125Ⅰ seeds were implanted into the tumor in experimental group while the empty seed was implanted in the control group at the same position as the experimental group. The experimental mice were executed after 24 d. Three tissues were cut from different positions according to the different distance （0.6, 1.2, 1.8 cm） from the implanted ^125Ⅰ seeds and the tumor cells were primarily cultured and the pathomorphological changes, growth and proliferation of tumor cells were dynamically recorded. Tumor cell count, efficiency and inhibitory rate of colony formation were calculated. RESULTS ： ① The cell number of experimental group was obviously fewer than that of control group at the same time point. There was a significant difference in the number of cultured cells from different positions of experimental group. ② The inhibitory rate of colony formation was 41.84%. ③ Variance analysis of total cloning efficiency of the cells from different positions showed a significant difference between experimental group and control group （ P 〈 0.01 ）, and among different positions of experimental group （ P 〈 0. 01 ）. CONCLUSION： The γ radiation from implanted ^125Ⅰ seeds directly destroys tumor ceils within the effective range. The radiation dose and killing effect of γ-ray decreased with the increasing distance from ^125Ⅰseeds.