Concentrated growth factors in the repair of a full-thickness condylar cartilage defect in a rabbit / 中国组织工程研究

ABSTRACT

BACKGROUND: Concentrated growth factors can promote the repair of tissue injuries. Its effect on the repair of condylar cartilage injuries is rarely documented. OBJECTIVE: To investigate the effect of concentrated growth factors on the repair of full-thickness condylar cartilage defects in rabbits. METHODS: Concentrated growth factors were prepared by collecting the venous blood of rabbits. A full-thickness cartilage defect penetrating the subchondral cortex was created at both sides of condyle in rabbits. The experimental side was filled with concentrated growth factors, and the control side healed naturally. The histomorphology was examined at 2, 6 and 12 weeks postoperatively. The degree of cartilage repair was evaluated by the modified Pineda cartilage repair scale. The release rate of concentrated growth factors was measured at different observational times. The study protocol was approved by the Experimental Animal Ethics Committee of Peking University Health Science Center (approval No. LA201809). RESULTS AND CONCLUSION: Fillings of fibrous and cartilage-like tissue in the defect were observed on both of the experimental and the control sides at 2 weeks postoperatively. Toluidine blue was stained homogeneously in the experimental side. Intercellular fibrous tissues with interpenetrating and heterogeneous toluidine blue staining appeared in the control side. At 6 and 12 weeks postoperatively, the repaired cartilage was identified in the experimental side. On the contrary, fibroid tissue hyperplasia was found in the control side, where toluidine blue staining showed no heterochromatin. Based on the modified Pineda cartilage repair score, the mean value of the total score in the experimental side was better than that in the control side at 6 and 12 weeks postoperatively. The difference in the mean value of the total score (P 0.05). ELISA tests showed that insulin-like growth factor 1, transforming growth factor β1, basic fibroblast growth factor, and vascular endothelial growth factor could be released continuously for more than 14 days. The release rates of these cytokines were decreased with time. These results indicate that concentrated growth factors can improve the early repair of full-thickness condylar cartilage defects in rabbits to some extent.