中文摘要：

目的 探讨采用犬股骨头负重区骨和天然软骨制备的骨-软骨双层支架复合成软骨诱导的骨髓间质干细胞（bone marrow mesenchymal stem cells,BMSCs）修复犬股骨头负重区大面积骨软骨缺损的疗效.方法 利用软骨细胞外基质作为软骨支架部分,犬股骨头负重区骨柱经脱细胞处理后作为骨支架部分,采用相分离技术制备骨-软骨双层支架.将成软骨诱导的BMSCs种植到双层支架上体外构建组织工程骨-软骨复合体,并以此修复犬股骨头负重区大面积骨软骨缺损（直径11 mm,高10 mm）,第3、6个月时分别取材,行大体、X线片、组织学、Micro-CT和生物力学等检测.结果 X线片及大体观察：3个月时可见股骨头负重区出现轻度塌陷;6个月时出现严重塌陷,呈重度骨关节炎改变.组织学观察：第3、6个月时软骨缺损部分均以纤维组织或纤维软骨充填,周围软骨退变,骨缺损部分不同程度塌陷,与宿主骨质结合紧密.第3、6个月时骨软骨缺损的骨体积分数均低于正常股骨头,差异有统计学意义.6个月时重建软骨下骨的刚度明显低于正常股骨头,差异有统计学意义.结论 结构性骨-软骨双层支架复合成软骨诱导的BMSCs修复犬股骨头负重区骨软骨缺损效果不佳,易导致股骨头塌陷.

英文摘要：

Objective To investigate the effects of the novel scaffold on repairing large,high-loadbearing osteochondral defects of femoral head in a canine model.Methods The biphasic scaffolds were fabricated using cartilage extracellular matrix （ECM）-derived scaffold （cartilage layer） and acellular bone matrix （bone layer） by phase separation technique.Articular high-load-bearing osteochondral defects with a diameter of 11-mm and the depth of 10-mm were created in femoral heads.The defects were treated with constructs of a biphasic scaffold seeded with chondrogenically induced bone marrow-derived mesenehymal stem cells （BMSCs）.The outcomes were evaluated for gross morphology,histological,biomechanical and micro-CT analysis at the third and sixth month after implantation.Results The gross and X-ray results showed femoral head slightly collapsed at the third month and severely collapse at the sixth month.Histological analysis showed cartilage defects were repaired with fibrous tissue or fibrocartilage with severe osteoarthritis and the varied degrees of the collapse of femoral heads were presented.Micro-CT showed that the values of bone volume fraction in defect area were always lower than those of the normal area in the femoral heads.Biomechanical analysis showed rigidity of the subchondral bone in defect area was significantly lower than that in normal area in the femoral heads at the sixth month.Conclusion The ECM-derived,integrated biphasic scaffold seeded with chondrogenically induced BMSCs could not successfully repair the large high-load-bearing osteochondral defects of the femoral head.