Cartilage Tissue Engineering

Extracellular matrix (ECM) is thought to participate significantly in guiding the differentiation process of mesenchymal stem cells (MSCs). In this study, we explored the hypothesis that osteoarthritic cartilage matrix can promote chondrogenesis of MSCs. Cartilage matrix was harvested from the health-like parts of osteoarthritic cartilage tissue. Cartilage fragments and MSCs were wrapped into fibrin glue; and the constructs were implanted subcutaneously into nude mice. Histological analysis showed a round and elongated cell appearance with positive Alcian blue staining of cartilage matrix formation in the constructs. However, the cells in fibrin glue only were condensed like MSCs in pellet culture. Immunohistochemical staining was abundantly positive for type II collagen in neo-cartilage regions of cartilage fragment-fibrin glue-MSC constructs, while the constructs without cartilage fragments were negative in staining for type II collagen. The gene expressions of type II collagen in the constructs with 60 mg fragments were significantly elevated after 4 weeks of implantation. Conversely, constructs without cartilage fragments failed to express type II collagen, which indicated that MSCs could not differentiate into a chondrogenic lineage. In conclusion, we demonstrated the effects of osteoarthritic cartilage matrix in promoting chondrogenic differentiation of MSCs. This was a favorable method without exogenous growth factors induction.