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<p><b>OBJECTIVE</b>To evaluate the effect of demineralized cancellous bone (DCB) seeded with allogeneic chondrocytes for repairing articular osteochondral defects in rabbits.</p><p><b>METHODS</b>Articular chondrocytes were isolated from a 1-month-old male New Zealand rabbit for primary culture. The passage 1 chondrocytes were seeded onto prepared rabbit DCB scaffold to construct tissue-engineered cartilage and cultured for 2 weeks. Full-thickness articular osteochondral defects (3 mm both in diameter and depth) were created on both sides of the femoral medial condyles in 30 New Zealand white rabbits (age 4- 5 months). In 20 of the rabbits, the defects were filled with the tissue-engineered cartilage on the right side (group A) and with DCB only on the left side (group B); the remaining 10 rabbits did not receive any implantation in the defects to serve as the control (group C). At 1, 3, and 6 months after the implantation, tissue samples were collected from the defects for macroscopic observation and histological examination with Toluidine blue (TB) and collagen type Ⅱ staining. The effect of defect repair using the tissue-engineered cartilage was assessed at 6 months based on the histological scores.</p><p><b>RESULTS</b>The prepared DCB had a spongy 3D structure with open and interconnected micropores of various sizes and showed good plasticity and mechanical strength. DCB began to degrade within 1 month after implantation and was totally absorbed at 3 months. At 6 months after implantation, the defects filled with the chondrocyte-seeded DCB were repaired mainly by hyaline-like cartilage tissues, which were well integrated to the adjacent cartilage without clear boundaries and difficult to recognize. The chondrocytes were located in the lacunate and arranged in vertical columns in the deep repaired tissue, where matrix proteoglycans and collagen type Ⅱ were distributed homogeneously close to the normal cartilage. The subchondral bone plate was reconstructed completely. The defects implanted with DCB only were filled with fibrocartilage tissue, as compared with fibrous tissue in the control defects. The histological scores in group A were significantly superior to those in group B and C ( < 0.05), but the scores for subchondral bone plate reconstruction were comparable between groups A and B at 6 months.</p><p><b>CONCLUSIONS</b>DCB is a good scaffold material for preparing tissue-engineered cartilage, and chondrocyte- seeded DCB can repair articular osteochondral defects by inducing the generation of hayline-like cartilage.</p>
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Objective Chondrocytes were seeded on allogeneic demineralized cancellous bone (DCB ) constructing tissue-engineered cartilage to evaluate the feasibility of DCB as scaffolds for tissue engineering cartilage.Methods Allogeneic DCB was prepared by successive defatting and decalcification and then observed under scanning electronic microscope.One-month old rabbit articular chondrocytes were isolated and proliferated by monolayer culture.Passage 1 chondrocytes were seeded on DCB to construct tissue-engineered cartilage in vitro for 6 weeks.Specimens were taken after 7,14,21,28,35 and 42 days'culture and evaluated by hematoxylin and eosin (HE),toluidine blue (TB),and immunohistochemistry for collagen type Ⅰ and Ⅱ.Results Prepared DCB showed three-dimensional porous structure of 100 - 500 μm with good plasticity and certain mechanical strength. Chondrocytes grew well on and inside the DCB,and were located in lacunae and expressed matrix proteoglycan and type collagen Ⅱ,which formed cartiageous tissues on DCB up to 42 days'culture.Conclusion DCB combined with allogeneic chondrocytes successfully constructed tissue-engineered cartilage in vitro ,which is an ideal scaffold for tissue engineering cartilage.
RESUMO
Objective Chondrocytes were seeded on allogeneic demineralized cancellous bone (DCB ) constructing tissue-engineered cartilage to evaluate the feasibility of DCB as scaffolds for tissue engineering cartilage.Methods Allogeneic DCB was prepared by successive defatting and decalcification and then observed under scanning electronic microscope.One-month old rabbit articular chondrocytes were isolated and proliferated by monolayer culture.Passage 1 chondrocytes were seeded on DCB to construct tissue-engineered cartilage in vitro for 6 weeks.Specimens were taken after 7,14,21,28,35 and 42 days'culture and evaluated by hematoxylin and eosin (HE),toluidine blue (TB),and immunohistochemistry for collagen type Ⅰ and Ⅱ.Results Prepared DCB showed three-dimensional porous structure of 100 - 500 μm with good plasticity and certain mechanical strength. Chondrocytes grew well on and inside the DCB,and were located in lacunae and expressed matrix proteoglycan and type collagen Ⅱ,which formed cartiageous tissues on DCB up to 42 days'culture.Conclusion DCB combined with allogeneic chondrocytes successfully constructed tissue-engineered cartilage in vitro ,which is an ideal scaffold for tissue engineering cartilage.