DU Mingª²Hua1, GAO Liª²Ning1, YAO Maoª²Yin2, GUO Jingª²He3

    1Department of Nuclear Medicine, 2Department of Urology, 3Department of Radiology, Zhongda Hospital, Southeast University, Nanjing 210009, China

    ¡¾Abstract¡¿ 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: ¢Ù 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. ¢Ú The inhibitory rate of colony formation was 41.84%. ¢Û 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 ¦Ã radiation from implanted 125I seeds directly destroys tumor cells within the effective range. The radiation dose and killing effect of ¦Ãª²ray decreased with the increasing distance from 125I seeds. ......