Transplantation of allogeneic chondrocytes cultured in fibroin sponge and stirring chamber to promote cartilage regeneration.

Cartilage regeneration using a fibroin sponge and a stirring chamber was investigated to improve the potential of articular cartilage tissue engineering. Chondrocytes seeded on the fibroin-sponge scaffolds were cultured in the stirring chamber (a bioreactor facilitating mechanical stimulation) for up to 3 weeks. Changes in DNA content, glycosaminoglycan (GAG) amount, integrin subunits alpha5 and beta1 fluorescence intensity, and morphologic appearance, were studied to evaluate tissue maturity. Seeded scaffolds subjected to the stirring chamber demonstrated significant increases in both DNA content (38.9%) and GAG content (54.3%) at day 21 compared to the control group. In addition, the stirring chamber system facilitated a maturation of cartilage tissue showed by histologic examination, after a staining of proteoglycan and type II collagen. Clinical feasibility of the fibroin and stirring chamber system was evaluated using rabbit models with cartilage defect. Large defects on rabbit knee joints were repaired with regenerated cartilage, which resembles hyaline cartilage at 12 weeks after operation. These studies demonstrated the potential of such mechanically stimulated scaffold/cell constructs to support chondrogenesis in vivo.