胶原／羟基磷灰石支架负载软骨细胞修复兔膝关节骨软骨缺损

Repair of knee joint articular osteochondral defects with collagen complex gradient hydroxyapatite biphasic scaffold loaded with chondrocytes in rabbits

目的探讨胶原复合梯度羟基磷灰石（Col／HA）双相支架负载软骨细胞修复兔膝关节骨软骨缺损的可行性及疗效。方法构建Col／HA双相支架，将软骨细胞种植于支架培养1周，再将软骨细胞-支架复合体移植修复兔膝关节股骨髁的骨软骨缺损，并对骨软骨缺损的修复进行检测。结果光镜及扫描电镜观察显示软骨细胞在Col／HA支架中贴附良好，表型维持稳定，分泌胞外基质。大体观察和组织学检测显示，植入体内16周后实验组软骨层呈透明软骨样修复，软骨下骨缺损有新骨构建；对照组骨软骨缺损修复不良，组织学检测以纤维性组织或纤维软骨组织形成。Wakitani评分显示实验组修复组织优于对照组，差异有统计学意义（P〈0．05）。结论双相Col／HA复合支架可作为骨软骨组织工程支架，负载软骨细胞可修复兔膝关节骨软骨缺损，重建关节软骨的结构和功能。

Objective To evaluate the effectiveness and feasibility for the treatment of osteochon dral defects on the femoral condyles by collagen/hydroxyapatite （CoL/HA） biphasie scaffolds loaded with the cultured articular cartilage ehondrocytes in rabbit knee joint. Methods Biphasic scaffolds were constructed with collagen complex gradient hydroxyapatite. The chondrocytes of third generation were embedded in the biphasic scaffolds＇ collagen. After culture for one week in vitro, the complexes of chondrocytesscaffold were transplanted to repair the articular osteochondral defects of the femoral condyle of rabbit knees （the defects were 4 mm in diameter, 3.5 mm in depth, extending down to the subchondral bone）. Healing of defects was assessed by gross and histological examination. Results Biphasic collagen/hydroxyapatite scaffold had good hydrophilia and permeability. Light microscopy and scanning electron microscopy revealed that chondrocytes attaching to the wall of microholes of the scaffold had largely maintained a rounded morphology and could secrete the extraeellular matrix on the porous scaffold. Gross and light microscopic examination showed that the treatment of simple Col/HA scaffold improved defect filling compared with that left untreated, while the regenerated tissue was mainly fibroeartilage and showed little bone formation. When implanted with CoL/HA scaffold combined with chondrocytes, most of the defects were filled with a well-established layer of cartilage tissue with new bone formation. Wakitani scoring showed that experimental group was superior to control groups in 16 weeks with the difference being significant between them （P 〈 0. 05）. Conclusion The novel biphasic collagen/hydroxyapatite scaffold will possibly be an ideal scaffold for osteochondral tissue engineering. It may induce articular osteochondral regeneration to repair the defects of articular osteochondral in vivo after loaded with chondrocytes.