Experimental Study On Repair Of Joint Osteochondral Defect With Chondrocytes Embedded In Fibrin Glue Fused On Autologous Bone

Objective To evaluate the possibility of repair of rabbit knee joint osteochondral defects with primary cultivated autologous chondrocytes embedded in FG fused on autologous bone, in order to explore a method of repair of osteochondral defect. To research the feasibility of using autologous bone fused with fibrin glue as a scaffold for osteochondral tissue engineering.Methods A total of 27 4-week-old new Zealand white rabbits were randomly divided into 3 groups of A (bone fused with FG + periosteum + chondrocytes), B (bone fused with FG + periosteum) and C (FG+periosteum), each group has 9 rabbits. Articular chondrocytes from the knee joints of the A group were separated respectively to fragments, and then digested by enzymes, both the chondrocytes and the uncomplite digested tiny chondral tissues have been cultured in vitro for about 2 weeks. Then the cultivated chondrocytes were embedded in fibrin glue fused on spongy bone, covered with priosteal flap; the complex was used to repair the femoral trochlea osteochondral defect which size is 3mm × 4mm × 4mm made in rabbit knee joint. In the B group, the osteochondral defect was repaired by complex of spongy bone fused with FG and periosteum, and the defect was treated with FG and periosteum in the C group. The rabbits were euthanized postoperatively at different intervals from 4, 8 and 12 weeks for macroscopic, histology, such like H-E stain, safranin-0 stain, toluidine blue stain.immunohistochemical stain and transmission electron microscope examination, and evaluated by O'Driscoll, Keeley and Salter scoring system.Results The results of cultivated chondrocytes were well-proliferated and well-regenerated, the most cells were round and the secreted extracellular matrix (ECM) was abundant. Autologous chondrocytes embedded in FG fused on spongy bone, and covered with priosteal flap, with which to repair the osteochondral defects. At 4th week, all groups FG have not been seen perharps because of biological degradation. In the A group, the defects were filled with smooth, semitransparent tissue that resembled articular cartilage after 4 or 8 weeks of implantation. The repair tissue was well bonded to the host cartilage tissue at the 12th week. In contrast, although a similar surface as the A group, the defects in the B group were restored mainly by fibrous cartilage in histological examinations. The special stains revealed the defects were filled with mature neocartilage in the A group. The histology indicated the B group was some of degeneration around the intervals between the repair tissue and the normal cartilage at the 12th week. The special stains also showed that the chondrocytes in neocartilage were some of well-distributed, part of chondrocytes were aligned in column, the positive result of immunohistochemical stain showed the osteochondral defects were repaired by hyaline or hyaline-like cartilage in the A group. However, immunohistochemical stain showed collagen II was negative in the B group. On the other hand, there was no obvious hyaline cartilage repair in the C group. At 8th week and 12th week, the differences of histological scores between three groups were statistically significant.Conclusions 1) The ways of transplantating primary cultivated chondrocytes embedded in FG fused on auologous spongy bone covered with periosteal flap into joint cavity can repair the osteochondral defects with hyaline or hyaline-like cartilage, it appears to be an ideal method for restoration of osteochondral defects, but further...