Tissue-engineered cartilage evaluation using the rabbit pinna punch model

Introduction. The aim of this study was to evaluate the use of tissue-engineered grafts in an in vivo model in the rabbit. Material and methods. Pinna multiple punch holes were made in the cartilage of the rabbit, measuring 6 mm in diameter, leaving the adherent skin intact. Ungrafted defects served as negative control; implantation of autologous auricular cartilage served as positive control. The defects were closed with various grafts (spongeous Demineralized Bone Matrix (DBM), alginate perichondrium, chondrocytes). Results. Implants of DBM with or without alginate showed closure of the defect with fibrous tissue only. When freshly harvested autologous chondrocytes were suspended in DBM+Alginate, islets of newly formed cartilage were observed. The best results were obtained with a newly engineered piece of cartilage. This was induced by subcutaneous implantation of bone material enrolled in perichondrium. This implant was extirpated after 3 weeks and placed in the defect; the cartilage graft, 6 weeks later, merged with the original pinna cartilage. Conclusion. Cartilage engineered in vivo by DBM and perichondrium functions as a viable and growing graft with excellent wound healing capacity. The rabbit pinna punch model is an effective and efficient way to evaluate cartilage grafts.