In vitro construction of scaffold-free cylindrical cartilage using cell sheet-based tissue engineering

Tissue-engineered cartilage may offer a solution for the treatment of serious airway disease. This study developed a novel procedure to fabricate a scaffold-free cylindrical cartilage under in vitro conditions, while also evaluating the effect of a dynamic culture on the engineered construct. Auricular chondrocytes were harvested from New Zealand white rabbits and cultivated under high-density conditions to form a chondrocyte sheet. The sheet was looped around a silicon tube and cultivated for 6 weeks in dynamic or static conditions. The engineered cylindrical cartilages were evaluated macroscopically and histologically. The expression of collagen, glycosaminoglycan content and mechanical properties were determined. The cylindrical cartilage was sufficiently elastic and stiff to maintain the structure without disruption. Histologically, the construct contained a Safranin-O positive cartilaginous matrix accompanied by the expression of type II collagen. The glycosaminoglycan content increased and reached 72% of the native tracheal cartilage after 6 weeks of cultivation. A novel procedure was developed for fabricating engineered cartilage, which maintained the shape and a proper level of rigidity and flexibility, under in vitro conditions using sheet-based tissue engineering techniques. This procedure may allow for the development of a tailor-made autograft and a functionally engineered trachea.