| Objective: Combined with computer-aided design/computer-aidedmanufacturing (CAD/CAM) technology and rapid prototyping (RP)technology, recombinant human bone morphogenetic protein-2(rhBMP-2),collagen type I, hydroxyapatite (HA) as materials, create personalizedartificial scaffold to repair the rabbit thyroid cartilage defects,seeking a newmethods to situ remediation of the thyroid cartilage defects, provided newtechniques and methods for the clinical personalization thyroid cartilagedefect repair and reconstruction.Methods: Foam gel prepared injection molding the different HA volumefraction (60%,50%,40%) of the standard sample (diameter10cm, high10cm cylinder) and conduct biomechanical testing.Using256layer CTscan the throat of New Zealand white rabbits, reconstruct the three-dimensional structure of the thyroid cartilage, midsagittal as the limit, usecomputer software to simulate the surgical removal of one side of thethyroid cartilage, the unresected side of the thyroid cartilage as the mirror,get the resection side mirror image of the structure, after three-dimensionalreconstruction of cartilage defects, using CAD software to complete theparting design of the fast mold, format to export the punch and mold as.STL. Use RP technology to reach the precisely stent mold manufacturingcontrolled; and recombinant human bone morphogenetic protein-2(rhBMP-2), collagen type I, hydroxyapatite (HA) as materials to reconstruct therabbit thyroid cartilage defects. Foam gel prepared injection molding thedifferent HA volume fraction (60%,50%,40%) of personalized scaffold,and detect its porosity. According to the the different HA volume fraction ofstandard sample biomechanics and artificial scaffold porosity test results,selected a suitable stent implant.Select32New Zealand white rabbits (male and female, female rabbit months of age6-10months the male rabbitsmonths of age8-10months, weighing2.5-3kg), randomly selected30intotwo groups, each group has15rabbits, midsagittal as the limit, remove oneside of the thyroid cartilage, group A for the defect area and implantedrhBMP-2/CHA composite scaffold,the B group defect area implanted CHAbracket;The bracket for the preoperative preparation of personalizedartificial scaffolds.1,3,7weeks after surgery, respectively, in each groupwere randomly selected five rabbits drawn gross observation, histologicalexamination, which after seven weeks in the two groups were randomlyselected four the rabbit line electronic laryngoscopy.In addition, two rabbitswere divided into group C,implanted non-personalized rhBMP-2/CHAbracket.Bracket substantially in accordance with the experimental animalswith unilateral thyroid cartilage produced,seven weeks after the surgery,laryngoscopy checks drawn line gross observation and histologicalexamination.Results:1The different HA volume fraction of standard sample biomechanics testresultsThe compressive strength in HA volume fraction of60%and50%wassignificantly higher than HA volume fraction of40%;the compressivestrength in HA volume fraction of60%was significantly higher thanHA volume fraction of50%;P <0.05for the difference was statisticallysignificance.2The different HA volume fraction stent porosity test resultsThe bracket porosity in HA volume fraction of40%and50%wassignificantly higher than HA volume fraction of60%;the bracket porosityin HA volume fraction of40%was significantly higher than HAvolume fraction of50%;P <0.05for the difference was statisticallysignificance.3Generally after surgeryPostoperative animals generally good, the day after operation all animalssobered and started drinking water,sound normal, start eating foods the nextday; the postoperative incision I/A heal without stitches, the line knot offon their own in about10days, the incision no significant bleeding, swelling,exudate and infection, purulent complications, no immune rejection.4Electronic laryngoscopy resultsSeven weeks after surgery in the two groups of A, B randomly selectedfour rabbit line electronic laryngoscopy, see: two groups of experimentalanimals throat mucosa no inflammation, no granulation, good vocal cordsclosed, no collapse occurred. C group of experimental animals throat mucosa no inflammation, no granulation, poor vocal cord closure, throatowe unobstructed.5Gross observationOne week after surgery, groupA and group B of materials are fibrousconnective tissue wrapped material partially degraded.The postoperative three weeks, groupA scaffold degradation, we can see asmall amount of translucent form bone nodules; group B scaffolddegradation, generated more fibrous connective tissue, no osteoid tissuecoverage.Seven weeks after surgery, group A scaffold material degradationcompletely defect massive bony tissue generated cut surface yellowish-white,hard texture, and newborn bone and contralateral close connection with theun-removal of the edge of the thyroid cartilage;Group B the bracket still sawfibrous connective tissue capsule;Group C scaffolds degradation completelydefect massive bony tissue formation, the cut surface of yellow-white, hardtexture, but the new bone contralateral resection of the thyroid cartilage edgewith less closely.6Histological examinationA group of one week: Inflammatory reaction, infiltration of neutrophilsand mononuclear histiocytes mainly common granulation tissue, visiblecapillaries of newborn,material partially degraded, the surgery area cartilageischemic necrosis, the edge of the area of cartilage cells reactive hyperplasia.A group of three weeks: The inflammatory response is not obvious,material degradation, accompanied by a large number of multi-core-liketissue proliferation and phagocytic partially visible mononuclear histiocyteshyperplasia; The surgical area Chondroblastoma hyperplasia with theformation of cartilage area;The surgical area microvascular hyperplasiamuscular angiogenesis.A group of seven weeks: The inflammatory response is not obvious,material degradation, accompanied by a large number of multi-core-liketissue proliferation and phagocytic the local visible mononuclear histiocyteshyperplasia; the surgical area Chondroblastoma hyperplasia with cartilageregion formation, the visible cartilage cells and cartilage bone formation.B group of one week: Inflammatory reaction,infiltration of neutrophilsand mononuclear histiocytes mainly common granulation tissue,visiblenascent capillaries,material part of the degradation,material around commonchildish fibroblasts, part of the regional fiber cell maturation. There were nocartilage cells and mature bone cells generated.B group of three weeks: The inflammatory response is not obvious,thematerial is completely degradable,accompanied by a large number of multi- core sample tissue and phagocytic,partly visible monocytoidhistocytosis,material around to see a lot of mature fiber cells. There were nocartilage cells and mature bone cells generated.B group of seven weeks: The inflammatory response is not obvious,thematerial is completely degradable,accompanied by a large number of multi-core sample tissue and phagocytic,partly visible monocytoidhistocytosis,material around to see a lot of mature fiber cells,part of the fibercell hyalinization. There were no cartilage cells and mature bone cellsgenerated.C group of seven weeks:The inflammatory response is not obvious,material degradation, accompanied by a large number of multi-core-liketissue proliferation and phagocytic the local visible mononuclear histiocyteshyperplasia; the surgical area Chondroblastoma hyperplasia with cartilageregion formation, the visible cartilage cells.Conclusion:1The combination of CAD/CAM, RP technology, using The the foamGelcasting method successfully prepared artificial scaffolds personalizedbracket anatomical shape, has good tissue compatibility and stabilitysupporting role.2rhBMP-2/CHA composite scaffold is closely integrated with the hosttissue, can be induced the formation of new cartilage defect site, has goodosteoconductive and bone-inducing activity is a new alternative in bonetissue engineering of bone tissue biologically active material and scaffolds.3The success of this experiment provide an experimental basis for the ofclinical thyroid cartilage personalized defect repair and reconstruction,alsoprovide new technologies and methods for future clinical application. |
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