| Experiment one:Preparation of the Radioactive Lacrimal Passages Probe and Study on Its Dose DistributionObjective To prepare radioactive lacrimal passages probe and observe the dose distribution in phantom, to obtain security indexes and therapeutic effective doses for brachytharepy. Methods Prepare radioactive probes by laying 125I particles into plastic tubes. Then, practice temperature tests, pressure tests, soak tests, shock tests to gain security indexes. The dose distributions in phantom and wax matrix were detected through thermoluminescent techniques, and the surface dose rates of different part of the phantom and operator were discovered with mobile dose rate detector. Results The radioactive lacrimal passage probe demonstrated no form changes in temperature tests, pressure tests and soak tests, with a surface radioactive contamination dose lower than 185Bq.However, the probe was waferinged in shock tests, meanwhile with a surface radioactive contamination dose lower than 185Bq.The dose detection in phantom and wax matrix show that during rangs from 1mm to 12mm off the tube, the absorbed dose (AD) changes had statistic significances as the distance added every 1mm(p<0.05). However, during rangs from 12mm to 40mm,the differences of absorbed doses had no significances(p>0.05) . Conclusion The dose rates of the lacrimal passages probe for brachytherapy is within safe limits for producers and operators, with therapeutic dose rates obtained. The lacrimal passages probe will be a useful and effective product for clinical therapy of lacrimal passages restenosis. Experiment two:Experimental Research on Inhibitory Effect of Radioactive Probe on Lacrimal Passage StenosisObjective To study inhibitory effect of radioactive probe on lacrimal passage stenosis. Methods Prepare inbred white rabbits to form lacrimal passage stenosis model and randomly divide into 3 groups, the stenosis group, probing group and radioactive probe group, with a control group of 5 rabbits. Rabbits in probing group and radioactive probe group were detected through DSA 10min and 30d after treatment before beening killed. While rabbits in stenosis group and control group were practiced DSA imaging 60min before the killing procedure. Morphological changes were observed through HE staining, while areas of lacrimal passage were viewed through computer based photo analysis. Results For probing group and radioactive group, the stenosis cure rate were 100%.While for probing group and radioactive probe group, the occurrence rates were 40% and 10% for specimens taken 10min and 30min, respectively. Average areas of lacrimal passages in control group, stenosis group, probing group and radioactive group were 0.84±0.28mm2, 0.26±0.13mm2, 0.55±0.31mm2 and 0.80±0.36mm2, respectively. Conclusion The radioactive lacrimal passage probe has distinct therapeutical effects in curing stenosis, with remarkable influences on preventing restenosis after the probing operation.Experiment three:Radioactive Lacrimal Probe's Influences on Expression of Bcl-2 and Bax Protein in Rabbit Lacrimal Passage Stenosis ModelObjective To observe influences of radioactive lacrimal passage probe on expression of apoptosis related protein bcl-2 and bax in rabbit lacrimal passage stenosis model. Method Prepare 30 inbred New Zealand white rabbits to form lacrimal passage stenosis model and randomly divide into 3 groups, the stenosis group, probing group and radioactive probe group, with a blank control group of 5 normal rabbits without any treatment.30 days after treatment, all experimental rabbits were killed and bilateral lacrimal passage stenosis tissue specimens were obtained. Expression of protein bcl-2 and bax in specimens were evaluated through immunohisto chemistry stain and compared between groups. Results Expressions of bcl-2 protein in epithelium and connective tissues of stenosis group and probing group were higher than that in blank control group (p<0.05),while expressions of protein bax in corresponding groups were lower than that in blank control group (p<0.05). Meanwhile, no protein expression difference was considered between stenosis group and probing group (p>0.05). However, expression of bcl-2 protein in epithelium and connective tissues of radioactive probe group was lower than blank control group (p<0.05), while expression of bax protein in corresponding group was higher than blank control group (p<0.05).Conclusion Radioactive probing therapy was able to decrease the ratio of bcl-2/bax through down-regulating protein bcl-2expression and up-regulating protein bax expression, which is a key factor to induce cell apoptosis and one of the therapeutical mechanisms of radioactive probe strategy for lacrimal passage stenosis.
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