Studies On Preparation Of Calcium Alginate Column And Its Combination With Chondrocytes For Articular Cartilage Defect Repair

Repairing articular cartilage defect has been a difficult task because of the poor ability of intrinsic cartilage repair. The concept of tissue engineering provided new methods for cartilage repair. Many problems still exist although great progresses have been achieved in various fields. This study aimed at obtaining experimental data for tissue engineering based on chondrocyte culture in vitro, preparation of calcium alginate scaffold and its combination with chondrocytes, ectopic neo-cartilage formation and joint cartilage defects repair in New Zealand rabbits. 1 Growth characteristics of rabbit chondrocytes cultured in vitro Aim: To investigate the growth characteristics of cultured rabbit articular cartilage chondrocytes and master the method of cell culture, provide experimental basis for the research on tissue-engineered cartilage. Method: Chondrocytes were harvested from slices of the young rabbit articular cartilage which were digested with enzymes for primary and passage culture in vitro. The following data were obtained: morphology, growth curve, adhesive rate of living chondrocytes. Result: Chondrocytes proliferated rapidly in vitro. The primary cells started rapid growth 72 hours after planting and kept satisfactory shape and function within six passages. The third to fifth passages seemed the most active. After long-term culture cell density increased evidently and secreted matrix which helped to form a membrame on theculture dish. Conclusion: Chondrocytes kept rapid proliferation rate and stable growth characteristics in vitro which might be useful for articular cartilage defect repair by tissue engineering method.2. Preparation of calcium alginate column and investigation of the structure Aim: Preparation of a novel cell scaffod which might act as a material carrier in cartilage tissue engineering research. Method: Calcium alginate column was obtained by thorough mixture of sodium alginate and calcium gluconate in certain ratio which experienced freezing and dehydration afterwards. Some of the columns were combined with chondrocytes and investigated for histological and SEM structure as well as those without chondrocytes. Result: The calcium alginate column showed open mesh structure of micropores with different sizes in the wall. Certain amount of chondrocytes could be found in the material meshes. After twenty-three-day's culture the material-chondrocyte construct kept original frame and structure. Round living cells existed among the nets. Conclusion: Calcium alginate column could be used as carrier of chondrocytes in the research on tissue-engineered cartilage formation.3 Ectopic cartilage formation using CaAlg-chondrocyte construct in the muscle pockets of rabbitsAim: The scaffold-chondrocyte constructs were implanted into the back muscle pouch of rabbits as allograft to investigate the ectopic cartilage formation, aiming at providing further supporting data on tissue engineering research. Method: The carrier-chondrocyte construct was implanted into the back muscles of rabbits by surgical technique. Histological examinations of the samples were performed at 2wk and 4 wk respectively after the operation. Result: Chondrocytes proliferated actively in the living body and new cartilage tissue could be found at the fourth week postoperatively. Conclusion: The calcium alginate combined with chondrocytes might play an active role in the research on cartilage tissue engineering.4 Animal experiment of full-thickness articular cartilage defect repair Aim: To observe the effect of CaAlg-chondrocyte construct on the repair of animal articular cartilage defect. Method: Twenty-six New Zealand rabbits were selected as experimental animals and full-thickness articular cartilage defects were created in the femur trochlea facing to patella. The defects were covered with chondrocyte-calcium alginate constructs, calcium alginate without chondrocytes, or nothing at all respectively. The result was investigated grossly and histologically at 4 > 8 > 12 ^ 24 and 28wk postoperatively. Resul...