A Pathophysiological Validation of Collagenase II-Induced Biochemical Osteoarthritis Animal Model in Rabbit

BACKGROUND: Current dilemma working with surgically-induced OA (osteoarthritis) model include inconsistent pathological state due to various influence from surrounding tissues. On the contrary, biochemical induction of OA using collagenase II has several advantageous points in a sense that it does not involve surgery to induce model and the extent of induced cartilage degeneration is almost uniform. However, concerns still exists because biochemical OA model induce abrupt destruction of cartilage tissues through enzymatic digestion in a short period of time, and this might accompany systemic inflammatory response, which is rather a trait of RA (rheumatoid arthritis) than being a trait of OA. METHODS: To clear the concern about the systemic inflammatory response that might be caused by abrupt destruction of cartilage tissue, OA was induced to only one leg of an animal and the other leg was examined to confirm the presence of systemic degenerative effect. RESULTS: Although the cartilage tissues were rapidly degenerated during short period of time upon biochemical induction of OA, they did not accompanied with RA-like process based on the histology data showing degeneration of articular cartilage occurred only in the collagenase-injected knee joint. Scoring evaluation data indicated that the cartilage tissues in non-induced joint remained intact. Neutrophil count transiently increase between day 8 and day 16, and there were no significant change in other complete blood count profile showing a characteristics of OA disease. CONCLUSION: These study shows that biochemically induced cartilage degeneration truly represented uniform and reliable OA state.

Disc-Type Hyaline Cartilage Reconstruction Using 3D-Cell Sheet Culture of Human Bone Marrow Stromal Cells and Human Costal Chondrocytes and Maintenance of Its Shape and Phenotype after Transplantation

In this study, we developed the disc-type bio-cartilage reconstruction strategies for transplantable hyaline cartilage for reconstructive surgery using 3D-cell sheet culture of human bone marrow stromal cells and human costal chondrocytes. We compared chondrogenesis efficiency between different chondrogenic-induction methods such as micromass culture, pellet culture, and 3D-cell sheet culture. Among them, the 3D-cell sheet culture resulted in the best chondrogenesis with the disc-type bio-cartilage (>12 mm diameter in size) in vitro, but sometimes spontaneous curling and contraction of 3D-cell sheet culture resulted in the formation of bead-type cartilage, which was prevented by type I collagen coating or by culturing on amniotic membrane. Previously, it was reported that tissue-engineered cartilage reconstructed in vitro does not maintain its cartilage phenotype after transplantation but tends to transform to other tissue type such as bone or connective tissue. However, the disc-type bio-cartilage of 3D-cell sheet culture maintained its hyaline cartilage phenotype even after exposure to the osteogenic-induction condition in vitro for 3 weeks or after the transplantation for 4 weeks in mouse subcutaneous. Collectively, the disc-type bio-cartilage with 12 mm diameter can be reproducibly reconstructed by the 3D-cell sheet culture, whose hyaline cartilage phenotype and shape can be maintained under the osteogenic-induction condition as well as after the transplantation. This disc-type bio-cartilage can be proposed for the application to reconstructive surgery and repair of disc-type cartilage such as mandibular cartilage and digits.