| Chitosan/β-glycerophosphate sodium is a thermosensitive material,and it isliquid at low or normal tempreture.when tempreture increases to37℃,the materialbecomes solidity like gels gradually,We use its thermosensitive property asexperiment basis,and probe whether the material is fit for embolism of arteriovenousmalformation.Firstly,Chitosan and β-glycerophosphate sodium are mixed to solutionby the scale of7:1,And we measure5spesmens,change of viscosity in their gelling at37℃,The result is that the viscosity reach a peak when time passes130s,We canconclude that time which Chitosan/β-glycerophosphate sodium solution of a scale of7:1become gel needs at least130s at37℃.We used an simple AVM model in vitro to do the embolic experiment,Twelvegrams of glass beads with a diameter of2mm were packed into a10ml disposableplastic syringe as an kind of deformed arteriolar,and the gap among glass beadsresemble lumina of defoemed vessels,One side of glass bead containers linked withthe physiological salt water bottles by infusion set as a supplied artery,and the otherside of the containers linked by infusion set with a diameter of2mm as drainingvenules,For imitating the intracranial pressure,The height of the saline bottle wasadjusted to150cm to maintain the saline flow rate through the column at0.3ml/s. Weput the containers soak in the thermostatic water bath at37℃,and the saline cycledwere heated up to37℃for cycle use,We embolized5models by Chitosan/β-glycerophosphate sodium solution with the same scale,Four models were allembolized successfully.There were no materials in the syringe set used inembolism,After embolism,we sealed the good embolitic containers and put in theconstant temperature box at37℃,The materials were not degradable and broken after6months,we opened these containers and observed that materials and beads wereadhesive closely,not degradable,and materials dispersed among beads very well.In vitro,the embolism experiment indicates that Chitosan/β-glycerophosphate sodiumcan effectively embolize AVM model as a thermosensative embolitic material,Itsdispersion effect is good,and embolitic time is controlled well,it needs further researchin vivo.Finally the material used as the embolism research in vivo,We choose renalartery and common carotid artery of rabbit as embolism object, Firstly,we selectednine rabbits,three one each group,the two groups used renal artery embolizationexperiment,and one group used to carotid artery embolization experiment. For renalartery embolization,we used the method of catheter intervention to do the abdominalaorta radiography with2ml contrast agents through femoral artery intubation and4Fradiography catheter, and clearly showed bilateral renal artery and its branches. Thenwe withdrawed radiography catheter, and changed microcatheter to put in the renalartery and fully showed the renal artery and its branches by radiography again. Weused1.5-2ml chitosan/β-glycerophosphate sodium solution to embolize renal arterysuccessfully.Embolitic materials can achieve renal artery secondary branches,immediately radiography after the embolism show that renal artery and its branches iscompletely blocked embolism by materials.The inject time of material was2minutesapproximately.There were no ectopic embolization, sticky pipe,and tube jamcomplications. The whole process and rinse catheter after embolization were carriedout smoothly,and we did not find tube jam phenomenon in catheter. In the threemonths observation period,we did not find renal artery recanalisation by radiography.Histopathological examination showed,after two weeks embolized kidney wasobviously pale,swelling,but another side kidney was normal, did not happenswelling.Kidney tissues HE dyeing,we could find the renal artery was embolized bymaterials completely,and there were organizing thrombus,metal particles in the lumenof vessels, But embolism materials falled off from some slices after dyeing,3monthsafter embolization,the embolized kidney decreased significantly,and becomedpale;Renal cortical becomed thin, and medullary happened serious liquefactionnecrosis.Histology showed that normal glomerulus structure completelydisappeared,replaced by fibrous tissue,and there was materials and metal particles inrenal artery lumen near the renal door,we did not find thumbus. For common carotid artery embolism,we injected directly into the material withsurgical operation method,It adopted the midline incision of neck,separated andexposed well common carotid artery, we used suture to ligate common carotid arteryat distal side,then clipped temporarily it in the proximal side by artery clamp,using1ml syringe extracted material with tantalum powder,the materials of0.2ml wereinjected to the common carotid artery from the ligation place proximal side,andcommon carotid artery was ligated at the place of puncture and syringe waswithdrawed at the same time,we put the embolized artery into tissue to keep warm.Five minutes later, we withdrawed vascular clip, and sutured fascia and skin step bystep. After3months, pathology examination showed, vessel and the surroundingtissue were adhesive closely, and it was not easy to separate. Pathology examinationshows that, there are organizing thrombus and materials in the lumen of vessels, Theexperiment in vivo proved Chitosan/β-glycerophosphate sodium has the gooddispersion ability and good resistance to high pressure blood blow.Throughtemperature sensitive characteristics measuring in vitro, and model AVM embolismtrail in vitro, and observation of the animal renal artery and common carotid arteryembolization effect, We can get a comprehensive evaluation thatChitosan/β-glycerophosphate sodium has a kind of potential as AVM embolizationmaterial.
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