ABSTRACT
BACKGROUND:A great development has been achieved in essential research on tissue engineered cartilage. However, its real application in otolaryngology has been rarely reported. It is faced with the topic to explore the simple and convenient method of repairing laryngeal cartilage by tissue engineering technique. OBJECTIVE:To compare the effect of porous spongy poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) seeded with chondrocytes or using senior tissue engineered cartilage in repairing al ogenic thyroid cartilage defects.METHODS:Chondrocytes at passage 3 were harvested from infant rabbits within 3 days. Porous spongy poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) seeded with chondrocytes composites were made by tissue engineering technique. The chondrocyte-poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) composites were co-cultured in vitro to form junior tissue engineered cartilage. And then respectively used for repairing the thyroid cartilage defects and directly transplanted with junior tissue engineered cartilage (experimental group A, n=5), or firstly the junior tissue engineered cartilage to be implanted subcutaneously for a period of time to further maturity for relative senior tissue engineered cartilage and secondly to be transplanted (experimental group B, n=5) into adult New Zealand white rabbits. Simple poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) sponge scaffold (control group A, n=4) and chondrocyte suspensions(control group B, n=4) were used as reparative materials in defect areas as control groups. Final y, the reparative effect was respectively studied grossly and histological y at 4 weeks (experimental group B) and 8 weeks (experimental group A, control group A and control group B) after transplantation. RESULTS AND CONCLUSION:The cartilage defects were wel repaired in the experimental groups. It was smooth between the reparative area and original cartilage without dents and defects. Both were similar grossly. But few chondrocytes at interfacial region between the reparative area and original cartilage and poor matrices were observed in the experimental group A. A Few chondrocytes and more matrices were observed in the experimental group B. Inflammatory cellinfiltration was not obvious in two experimental groups. Control groups showed soft tissue of dark-red color accompanied with local concave in gross specimens. Histological examination and special staining showed there were no cartilage-like structure and secretion of matrix components. The results showed that it is possible to repair thyroid cartilage defect using junior tissue engineered cartilage directly or junior tissue engineered cartilage after in vitro implantation in al ograft rabbits with immunity, and the immunoreaction is not obvious;in the same period, the repairing effect of mature tissue engineered cartilage is better than that of junior tissue engineered cartilage. However, application of junior tissue engineered cartilage directly can save time, costs, workload and operational link, and avoid the pain from secondary skin surgery, which is one of the more practical approaches.