OBJECTIVE: To study the effect of laryngeal cartilage defect repair with differently preserved allogeneic cartilage grafts.METHODS: 16 New Zealand white rabbits were used and divided into two groups. A 6 mm x 3 mm x 1 mm whole thickness cartilage defect was made in each side of the thyroid cartilage of each rabbit. In group one, the tissue-cultured cartilage grafts, preserved in RPMI-1640 medium for 30 days, were implanted in the left defects and the 4% formaldehyde preserved cartilage grafts for 30 days were implanted in the right defects. Fresh autogenous and allogeneic grafts were seprately transplanted into the right and left thyroid cartilage defects of the other group. Thyroid cartilages were taken out at 7, 30, 180 and 360 days after implantation. Samples were observed by macroscopy and prepared for hematoxylin and eosin (H&E) staining and immunohistochemical examination.RESULTS: No marked changes in form and volume were found in the fresh allografts and RPMI-1640 cultured cartilage grafts. The same as the autogenous cartilages, the defects of thyroid cartilage were successfully repaired by the fresh allografts and RPMI-1640 cultured cartilages. Whereas 4% formaldehyde preserved cartilage grafts were completely absorbed and replaced by cicatricial tissues in the thyroid cartilage defects. Histological observation showed that severe inflammatory cellular infiltration in the formaldehyde preserved cartilages at 7 and 30 days. The cartilage matrixes were resorpted and the chondrocytes showed degenerative change. Finally they were replaced by fibrous connective tissue at 360 days. In the RPMI-1640 cultured and fresh allogeneic cartilages only a little inflammatory cellular infiltration was observed and the cartilage matrixes were almost normal from 7 to 360 days.CONCLUSION: It is clinically feasible to use allogeneic grafts stored in RPMI-1640 medium or fresh allogeneic cartilage grafts for repairing laryngeal cartilage defects.
Animals Female