| Nowadays, no perfect methods are performed to repair cartilage defects caused by diseases or traumas in larynx and trachea. Although autologous, allogeneic cartilage and artificial products are usually used as reparative materials to reconstruct laryngeal and tracheal function, these methods still remain unsolved problems which are the damage to donor, lack of enough cartilage, no suitable shape for recipient, immune rejection from recipient, foreign body reaction and difficult blending with recipient. Therefore, it is still an important task for the otorhinolaryngeal workers to explore a new way of cartilage reconstruction. In recent years, tissue engineering technique provides a effective approach for solving these problems. Tissue engineering is a multidisciplinary scientific field merging with biology, material science, engineering and chemistry. Its main idea is to harvest minimal quantity of tissue cells, and then expand them in vitro. Next, the cells are seeded onto a3. Laryngeal cartilage defects repair with chondrocyte-PGA complexes.18 adult male New Zealand White Rabbits (age:4~6 months, weight : 2.5kg?.5kg) were at random divided into experimental groups(n=6). 0.6cmX 0.5cm cartilage defect sites were created just as experiment 2.Then,defects were repaired using chondrocyte-PGA complexes in experimental groups;in control A groups,defects were repaired using single PGA biomaterials.200 ul chondrocyte suspension with cellular density of 6X 107/ml was injected into defect sites in control B groups.Finally.the reparative effect was studied on gross and histology in 4,8 and 12 weeks after surgery.Results1. Chondrocytes culture in vitroIt took about 48-72 hours to adhere to the dishs for primary chondrocytes.During subculture.the time gradually became shorter.After seeding chondrocytes onto PGA scaffolds,cells maintained their spherical shape and adhered to the PGA fibers in the form of a string of beads or multiplayer.A number of matrices like web amoung fibers were observed around one week after culture in vitro.2. Gross and histology ofallogeneic tissue engineered cartilage4 weeks after transplantation,the specimens were excised. On gross examination, sheets and "C" shaped specimens appeared milk white cartilage tissue of approximately the same shape as the original configuration. Histologicalanalysis.the immature chondrocytes had been regenerated in allograft animals. Some mild inflammatory cells surrounding the new cartilage and a few PGA fibers were observed(HE stain ). Light-green staining of collagen and purple-blue staining of sulfated glycosamioglycan(GAG) within the cartilage matrix were detected. 8 weeks after transplantation, mature cartilage similar to native cartilage structure was found.The formation of lacunae in which the single or multiple chondrocytes were enclosed was observed .More collagen and sulfated GAG were found.Less evidence of inflammatory cells response and residual PGA fibers were watched. 12 weeks after transplantation,more mature cartilage was obtained.There was no evidence of neovascular formation. No chondrocytes and their matrice were also seen in control groups.3. Observation ofreparative effect -with tissue enginnered cartilage4 weeks after operation,gross specimens showed that laryngeal thyroid cartilage defects were well repaired using allogeneic tissue engineered cartilage as reparative material. Histological examination found a few chondrocytes and matrices between the reparative sites with tissue engineered cartilage and normal cartilage.But chondrocytes was smaller in repartive sites than that in native cartilage sites.8 and 12 weeks after operation,more chondrocytes and matrice were observed in reparative and interfacial areas.Few inflammatory cells were found.Only connective tissue existed in reparative sites of control groups.4. Observation ofreparative effect with chondrocyte-PGA complexes4 weeks after operation, gross inspection showed that cartilage defect areas were initially repaired .Histolog...
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