Study Of Articular Defect Repaired By Chondrocytes Cultured In Alginate In Rabbits

Objective To observe the biological characteristics of chondrocytes cultured in alginate and long term results of articular defect repaired with the cultured chondrocytes and alginate compound.Methods Chondrocytes from the knee joints of 34-weeks-old New Zealand white rabbits were obtained using collagenase enzyme.The chondrocytes were mixed with alginate in a cell density of 4×10⁶/ml.The suspension was gelled in a shape of disc in CaCl₂ solution and each disc contains 20ul suspensions.The discs of chondrocytes and alginate compound were cultured in 24-Multiwell.The discs were taken at the end of 2,4,6,8 and 10 weeks after culture,and were used for evaluation of proteoglycan and collagenâ…¡with HE and AB-PAS staining,biochemical analysis,immunohistochemistry and transmission electron microscopy.28 adult New Zealand white rabbits were chosen,and full-thickness articular defect with a diameter of 3.5 mm was produced in the femoral condyle of both knee joints.A disc of chondrocytes and alginate compound cultured four weeks in vitro was implanted in one side and a disc of alginate without chondrocytes in another side randomly.The femoral condyles were harvested at the end of 6,12,24,and 48 weeks for observing the repair.Result Chondrocytes from the adult rabbits grew in cluster and proliferated at the highest in 4 weeks.They showed round shape during the culture.The proteoglycan secreted from the cultured chondrocytes increased obviously.There is a strong staining of collagenâ…¡,but no collagenâ… ,with immunohistology.Ultrastructure of chondrocytes did not show abnormal change by electron microscopy.The animal study showed that the defect repaired with hyaline-like cartilage in experimental group,while fibrous tissue in the control. However,both groups showed degenerated changes of reparative tissue at 48 weeks follow-up.Conclusion The chondrocytes from the adult rabbits cultured in alginate can keep the phenoshape and construct engineered cartilage tissue in vitro.Implantation of engineered cartilage tissuein articular defect can produce the hyaline-like cartilage.