| Background: With the development of medical science and technology, the identification and utilization of new nuclide, more and more radioactive nuclide has been utilized for brachytherapy of tumor. The research of this field is also more active recently. Among radioactive nuclides, 125I seed is one of the most frequently utilized nuclides in tumor therapy. Its physical feature, dosimetric characteristics and the biology principle of therapy have been widely and deeply investigated. Bladder cancer is a high-occurred malignant urinary tumor. The previous research on its radiotherapy is limited in in vitro and in cavity therapy. The practice of interstitial implanting 125I seed to treat tumor and its basic biological principle has not been reported.Objective: Through the experimental research of the biological effect of implanting 125 I seed to treat bladder cancer, in order to get insight of the mechanism of implanting 125I seed to kill tumor and to provide academic gist and practice guidance for clinical utilization of 125I seed for brachytherapy of bladder cancer. Methods: 16 T139 inbred line mice were divided into two groups (A: experimental, 8; B: control,8) in random; bladder cancer model was founded via tumor source transplant. When the transplanting tumor grow observable, implanted 125I seed in tumor of experimental group, executed mice after 24 days. Observed the long diameter (a) and the short diameter (b) of tumor body every 3 days, calculated the volume of tumor body (V=ab2/2), the weight of mouse (W), the weight of tumor body after execution of mice (w), protracted the growth curve of tumor, calculated the colony redouble time and tumor suppression rate. After fixation of formaldehyde, observed the pathological modality of tumor tissue with HE staining. Cut three tissue of different distance according to the implant position, primarily cultured the tumor cell, and dynamically observed the shape change, growth and proliferation of cell with microscope, culture tumor cell and numeration, recorded the colony form rate and the suppression rate of colony formation. Results: (1): the latent period of transplant tumor was 4.3+0.6 days; the diameter of tumor was 0.7cm one week after transplantation. The transplantation was 100% successful and there was no natural fadeaway phenomenon. (2): after implantation of seed, the weight of A group mice increased 4.93+0.60g, that of B group increased 13.60+1.15g(P<0.05). (3): after execution, the weight of tumor body of A group mice was 7.86+0.59g, that of B group was 9.06+0.27g(P<0.05). (4): tumor suppression rate was 13.24%. (5): the colony redouble time of tumor cell was 3~6 days. After implantation of seed, the tumor body volume of A group increased 10.84+1.10 cm3. That of B group increased 13.57+0.65cm3. The tumor growth of A group was suppressed (P<0.05). (6): the suppression rate of colony formation was 41.84%. (7): through variance analysis of total colony formation rate of the cell from different positions, it was found that there was significant difference between A group and B group (P<0.01), among different positions of A group (P<0.01), but there was no difference among different positions of B group (P>0.05). (8): pathological histology: there is hemorrhage and necrosis area in the center of tumor of some mice in control group, the necrosis position are few and the necrosis areas are small. Around the implant position of seed of experimental group, there were large necrosis area, scattered and abnormal small necrosis area could also be observed. (9): the growth characteristics of cultured bladder cancer cell: the cell began grow after 12hrs of seeding. After 5 days, the cell entered exponential growth phase and the nuclear division could be observed. After 8~10 days, the cell began fusion to form like slabstone. The cell number of A group is obviously fewer than that of B group of the same time point. The cell shape was abnormal and the cells adhered to wall left the cell glass wall and turn round. There was significant difference of the number of... |
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