| The whole experiment is divided into three parts:1. Exploring the acting range of the Holmium laser ablation to porcine pancreas:an animal study in vitroObjective: To explore the acting scope of holmium laser ablation on vitro porcinepancreas in different parameters setting and to obtain the linear regression equation ofholmium laser ablation on pancreas, in order to provide the experimental basis ofholmium laser ablation with EUSguided to pancreatic cancer in clinical practice.Methods: A randomization table was designed by different combination of fiveenergies, five times and five frequencies. The total sample size was125. The125vitroporcine pancreases were ablated by holmium laser continuously based on therandomization table. Ultrasound sonogram changes were observed during holmium laserablation. The ablative range was measured with naked eye and the volumes wascalculated by the formula: V=4/3πabc, and the ablative tissue was retrieved forhistopathological examination with hematoxylin and eosin staining staining.Results: The linear regression equation was successfully established. The ablatedrange was approximate ellipsoid body, the middle of which was carbonation andsurrounding gray-white necrotic area. The main factors affecting the ablative range wasfrequency, second was the time and energy was again, which difference showed astatistically significant. Hematoxylin and eosin staining revealed a coagulation necrosisperformance in ablation lesion.Conclusion：The holmium laser ablation acting on the vitro porcine pancreas couldproduce significant tissue necrosis. The created regression equation could be a referenceof holmium laser ablation.2. EUS-guided Holmium: yttrium aluminum garnet laser ablation of orthotopicpancreatic tumor in nude miceObjective: To explore the safety and efficacy of holmium laser ablation oforthotopic implantation tumor.Methods: Orthotopic pancreatic tumor models were established in twenty nude mice,which were assigned into two groups of ten randomly: the study group and the controlgroup. EUS-guided holmium laser was punctured into the pancreatic tumor of the studygroup with an optical fiber. The total delivered energy was1J and frequency was5Hz in a continuous mode of5S. The volumes of pancreatic tumors after ablation were measuredunder EUS at the first week, the second week and the fourth week. The histological tissuewas obtained at four weeks following measurements.Results: The successful rate of model was100%. All the nude mice could toleratethe procedure and no complications in the study group nude mice. The coagulationnecrosis, localized in the middle of ablated area, was observed in the study group onhistological examination. The volume of the tumor was559.4±165.9mm3and159.9±66.8mm3before and after ablation in the study group, while427.0±174.4mm3and881.4±243.6mm3, respectively in the control group. The difference between study groupand control group showed an evident statistically significance.Conclusion: EUS-guided holmium laser ablation of orthotopic pancreatic tumor issafe and effective in a nude mice model. The main performance is coagulation necrosis ofablative tissue.3. The expressive trend of heat shock protein70in pancreatic xenograftsofnude mice following EUS-guided holmium laser ablationObjective: To explore the expressive characteristic and trend of heat shock proteinsin the xenografts of pancreatic tumor of transition zone in nude mice after EUS-guidedholmium laser ablation. As to whether the heat shock protein can be used as the judgmentof treatment and prognosis of holmium laser ablation.Methods: Thirty xenografts modes were separated into five groups of six. Five ofeach group, which was called the experimental group, underwent holmium laser ablation.The remaining one of each group as control group was received no treatment. The ablatedtissue was obtained and analysed at the following time points:0,12,24,48h and7d afterablation by hematoxylin and eosin staining, immunohistochemistry (IHC), Western blot(WB) and real time PCR (RT-PCR) for HSP70expression.Result: This was more prevalent in the nude mice that was tolerated the procedure.H&E staining revealed the coagulation necrosis of ablated area. HSP70was expressed inthe transition zone at0h, peaked at12h, a gradual decline at48h, repeated elevated at7dthrough the detection of IHC, WB and RT-PCR.Conclusion: The repeated increased HSP70add the immunogenicity of tumor cell intransition zone, which was crucial to the treatment effectiveness and prognosis. |
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