Affiliations: Institute for Frontier Medical Science, Kyoto University, 53 Kawahara‐cho, Shogoin, Sakyo‐ku, Kyoto 606‐8507, Japan | Kyoto University International Innovation Center, Yoshida‐honmachi, Sakyo‐ku, Kyoto 606‐8501, Japan | Department of Orthopaedic Surgery, School of Medicine, Toho University, 6‐11‐1 Omorinishi, Ota‐ku, Tokyo 143‐8541, Japan | Department of Orthopaedic Surgery, Shinshu University School of Medicine, 3‐1‐1, Asahi, Matsumoto, Nagano 390‐8621, Japan | National Institute of Sericultural and Entomological Science, 1‐2 Owashi, Tsukuba‐city, Ibaragi 305‐8634, Japan
Note: [] Corresponding author: Naohide Tomita, Kyoto University International Innovation Center, Yoshida‐honmachi, Sakyo‐ku, Kyoto 606‐8501, Japan. Tel. & Fax: +81 75 753 9200; E‐mail: [email protected]‐u.ac.jp.
Abstract: The dynamic visco‐elastic properties of regenerated cartilage tissue were measured to evaluate its mechanical function during cultivation. Harvested chondrocytes from 4‐week‐old Japanese white rabbits were inoculated into fibroin sponge at a cell concentration of about 5×107 cells/ml. Dynamic visco‐elasticity measurements were performed under compressive loading to evaluate the load bearing function of the articular cartilage. The dynamic modulus and the dynamic loss of the regenerated cartilage increased and the peak value of tanδ, as well as the frequency at the peak, decreased with increasing cultivation time. The pores of the fibroin sponge became filled with newly formed tissue as cultivation time increased. These changes in the visco‐elastic properties of the regenerated cartilage were compared with those of a model system, ethylene propylene diene monomer sponge with interstitial fluid, and appear to be a result of increased fluid flow resistance and internal loss. We conclude that the changes in the dynamic visco‐elastic properties of the regenerated cartilage were caused because of narrowing of the fluid path by synthesized extracellular matrix.
