Abstract:

BACKGROUND: Effective repair of articular cartilage defects and achieving a good long-term efficacy using tissue engineering methods remain unclear. The research group proposed an experimental hypothesis that “allogeneic bone marrow mesenchymal stem cells in articular cavity culture tissue engineered cartilage”.
OBJECTIVE: To demonstrate the role of allogeneic decalcified bone matrix combined transforming growth factor β1 and insulin-like growth factor Ⅰ to differentiate bone marrow mesenchymal stem cells (MSCs) into cartilage, and to investigate the method of promoting differentiation into articular cartilage by the culture in articular cavity.
METHODS: Bone marrow MSCs were separated and cultivated in vitro. In experimental group, transforming growth factor β1 and insulin-like growth factor Ⅰ were applied into DMEM to induce proliferation and chondrogenic transformation, while in control group only DMEM was used. The proliferation and chondrogenic transformation between two groups were compared. Allogeneic decalcified bone matrix was prepared, bone marrow MSCs in the experimental group were seeded into the decalcified bone matrix, to construct tissue engineered cartilage complex, which was then place into knee cavity of 30 rabbits after parceled with fascia. At 4, 8, 12 weeks following implantation, ten specimens were selected for histological section observation and type Ⅱ collagen immunohistochemistry staining.
RESULTS AND CONCLUSION: Colony forming efficiency in experimental group was significantly higher than that of control group (u=3.326, P < 0.01). Immunohistochemical identification of type Ⅱ collagen was positive in experimental group, while negative in control group. At 12 weeks after the tissue engineered complex were cultured, hematoxylin-eosin staining showed that a large amount of chondrocytes began to proliferate, caryon was stained blue. Toluidine blue staining showed that the chondrocytes aligned, there were plenty of cartilage lacunas, and were surrounded by lots of extracellular matrix. Immunohistochemical identification of type Ⅱ collagen was strongly positive, lots of brown-yellow stained particles could be discerned in extracellular matrix. Bone marrow MSCs proliferation and differentiation into chondrocyte can be significantly promoted by the synergistic action of transforming growth factorβ1 and insulin-like growth factor Ⅰ. MSCs combine with decalcified bone matrix can successfully cultivate tissue engineered cartilage in articular cavity. Allogeneic decalcified bone matrix may satisfy the demands of tissue engineered cartilage scaffold.