Allogenic chondrocytes loaded with liquid or gel biocarrier material in repairing full-thickness rabbit articular cartilage defects / 中国组织工程研究

ABSTRACT

BACKGROUND: It has been successful to repair articular cartilage defects by using solid carrier as cytoskeleton. We tried to transplant liquid or gel carrier materials combined cells into the body of animals, and investigated its feasibility.OBJECTIVE: To investigate the feasibility of homo-transplatation with liquid or gel carrier materials of Pluronic F-127-recombinant human bone morphogenetic protein-2 (rhBMP-2) engineered chondrocytes for the repair of full-thickness rabbit articular cartilage defect.DESIGN: A controlled experiment.SETTINGS Department of Orthopaedics, Weihai Municipal Hospital;Shandong Institute of Orthopaedics and Traumaology.MATERIALS The experiments were carried out in the laboratory of Shandong Institute of Orthopaedics and Traumaology from November 2001 to September 2003. Thirty-six healthy adult New Zealand rabbits of 2.5-4.5 kg, either male or female, were divided into four groups according to the method of random number table Pluronic F-127-rhBMP-2 engineered chondrocytes group, Pluronic F-127-rhBMP group, Pluronic F127 engineered chondrocytes group and blank control group, with 9 rabbits in each group.METHODS: After grouping, the 36 rabbits were made into models of articular cartilage defects. Pluronic F-127-rhBMP-2 was used as a vector of chondrocytes which were obtained from New Zealand rabbits after cultured and amplified in vitro. The mixture of Pluronic F-127, Pluronic F-127-rhBMP-2 and cultured chondrocytes was transplanted into the defects of articular cartilage that had been made previously with φb3.5 mm drill.There was not any treatment in the blank control group. At 4, 8 and 12 weeks postoperatively, the repairing conditions of the defects were evaluated with gross observation and histological observation under light microscope and under electron microscope. The repaire quality was assessed blindly according to the Wakitani scoring standard.MAIN OUTCOME MEASURES: ① Healing of cartilage defects; ② Property and morphology of the chondrocytes, characteristics, number and arrangement of collagens in matrix.RESULTS: ① In the Pluronic F-127-rhBMP-2 engineered chondrocytes group, the transplanted chondrocytes could grow better than those in other groups, the defected areas were completely filled at 4 weeks. The regenerated tissues at 8 and 12 weeks had similar appearance with the surrounding normal cartilage tissue, but vague. Delimitation. The histological examination showed that transparent cartilages formed, and the defects were healed. ② Under electron microscope at 8 and 12 weeks, there were mature transparent cartilages in the repaired tissues, and there were irregularly arranged slight, even and non-periodical collagen Ⅱ in surrounding. In the blank control group, only fibrous repair was observed, the regenerated tissue lacked elasticity with rough surface. ③ Repairing quality score The scores at each time point in the Pluronic F-127-rhBMP-2 engineered chondrocytes group were significantly different from those in the other groups.Those in the Pluronic F-127-rhBMP-2 engineered chondrocytes group and Pluronic F-127-rhBMP-2 group and Pluronic F-127 engineered chondrocytes group were significantly different from those in the blank control group [4 weeks (3.93±1.91), (4.56±1.07), (4.78±1.09), (8.44±1.13) points8 weeks (2.80±1.45), (3.24±1.00), (3.33±1.00), (8.44±1.13) points; 12 weeks (2.22±1.10), (3.01±0.69), (3.00±0.71), (9.00±0.87) points, P ＜ 0.001],but there were no significant differences between the two groups (P ＞ 0.05).CONCLUSION: The mixture of Pluronic F-127-rhBMP-2 and cultured chondrocytes can repair successfully the cartilage defects of femoral condyle of rabbit knees by means of hyaline cartilage than simple application of Pluronic F-127-rhBMP-2 or Pluronic F-127 engineered chondrocytes.