Local treatment of cricoid cartilage defects with rhBMP-2 induces growth plate-like morphology of chondrogenesis.

Abstract

The ultrastructural characteristics of new bone and cartilage, induced at the site of cricoid cartilage defects treated with rhBMP-2 in rabbits, were investigated. A cricoid defect model was used. Fifteen rabbits were randomly and equally divided into 3 groups. Four rabbits from each group were treated with rhBMP-2, while one rabbit from each group was used as control. The rabbits were killed 1, 2, or 4 weeks after surgery. The healing pattern of the laryngeal wound was evaluated by light and transmission electron microscopy. Mineralized collagen type I matrix, osteoblasts, and osteoclast-like cells were present as early as 1 week after surgery. Well-structured bone trabeculas and growth plate-like structures were present 4 weeks after surgery. Intramembranous and endochondral osteogenesis take place at the site of cricoid cartilage defects treated with rhBMP-2. Progenitor cells of cricoid perichondrium form a growth plate-like structure similar to the epiphyseal growth plate. This study reveals the pattern of BMP-2-induced repair of airway cartilage defects.