不同方法诱导的兔骨髓间质干细胞对关节软骨缺损修复效果及退化的影响

Influences of different inductive methods on cartilage repair by tissue engineered cartilage with rabbit mesenchymal stem cells

目的:以兔骨髓间质干细胞为种子细胞,探讨不同诱导方法对组织工程移植物修复关节软骨缺损的效果及退化的影响。方法:将兔骨髓间质干细胞分为地塞米松诱导组和TGF-β1加地塞米松联合诱导组进行体外诱导,采用自体组织工程移植物修复关节软骨缺损;对照组缺损填充无细胞单纯载体。于术后6和12周对修复组织进行组织学观察、评分及TUNEL原位凋亡检测。结果:联合诱导组,修复组织形成理想的柱状结构,术后12周组织学评分(20.26±1.35)优于对照组(4.12±1.13)及地塞米松组(14.52±1.46),但修复组织未形成潮线。在骨软骨交界处软骨细胞TUNEL染色阳性,地塞米松组术后6周修复组织TUNEL染色阳性细胞记数为21.4±4.5,术后12周为7.3±2.2;联合诱导组术后6周为19.8±4.7,术后12周为6.9±2.0,术后12周与术后6周比较差异有显著性(P<0.05)。结论:组织工程移植物的修复效果以联合诱导组为佳,且退化发生较晚;组织工程移植物的退化与移植前诱导条件、细胞凋亡及软骨下骨板内血管系统有关。

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 perpendicular 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-cartilage 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 in TGF -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 postoperatively with statistical significance （P〈 0.05）. Conclusion The TGF -β1 and dexamethasone co-inducing group shows better repair of the cartilage defect and more slight and later degeneration of the repair tissue. The degeneration of cartilage tissue engineering transplant is correlated with the inducing environment prior to transplantation, apoptosis, and the subchondral vascular system.