关键词: 骨髓祖代细胞, 软骨, 退化, 细胞凋亡

Abstract: Objective To explore the influences of different inductive methods on cartilage repair by tissue engineered cartilage with the seed cell of mesenchymal stem cells. Methods Rabbit mesenchymal stem cells were divided into dexamethasone-inducing group and TGF-β₁-dexamethasone co-inducing group. The cartilage defects were repaired by autologous tissue engineered cartilage constructs. The defects of control group were filled with scaffold without cells. Specimens were harvested 6 and 12 weeks postoperatively and assessed by histological grading and in situ detection of apoptosis. Results The repair tissue formed perpendicurar column structure resembling that of normal cartilage in TGF-β₁-dexamethasone co-inducing group. The histological score 12 weeks postoperatively was higher in co-inducing group (20.26±1.35) than those in dexamethasone-inducing group (14.52±1.46) and control group (4.12±1.13). But the formation of tidemark was not observed in the repair tissue. Cells of repair cartilage at the bone-car tilage interface showed apoptosis. The ratios of apoptosis in dexamethasone-inducing group were (21.4±4.5) six weeks postoperatively and (7.3±2.2) twelve weeks postoperatively. The ratios of apoptosis inTGF-β₁-dexamethasone co-inducing group were (19.8±4.7) six weeks postoperatively and (6.9±2.0) twelve weeks postoperatively. The ratios of apoptosis at 6 th week were higher than those at 12 th week postopera tively with statistical significance(P<0.05). Conclusion The TGF-β₁ and dexamet hasone co-inducing group shows better repair of the cartilage defect and more slight and later degeneration of the repair tissue. The degeneration of cartilagetissue engineering transplant is correlated with the inducing environment prior to transplantation, apoptosis, and the subchondral vascular system.

Key words: myeloid progenitor cells, cartilage, degeneration, apoptosis