Repair of osteochondral defect with tissue-engineered osteochondral composite graft / 中华骨科杂志

ABSTRACT

Objective The tissue-engineered composite graft was formed with induced marrow-derived stromal cells (MSCs)and PLGA double-layer scaffold. The effectiveness of this graft for the repair of osteochondral defects in the knee of rabbits was investigated. Methods MSCs were isolated from 20 adult rabbits with density gradient centrifugation and was divided into two groups. In group A, the MSCs were cultivated with regular medium. In group B they were cultivated with chondrogenic differentiation medium. The mRNA of MSCs and articular cartilage cells were extracted, and the expression of mRNA for type Ⅰ and Ⅱ collagen was tested by RT-PCR. The distribution and compound of MSCs with PLGA double-layer scaffold was examined with scanning electron microscopy. 28 adult rabbits were divided into 3 groups, osteochondral defect of 3.5 mm in diameter and 3 to 4 mm in depth were created in the patellar groove. Group A (10 rabbits), the MSCs cultivated with regular medium was grafted into the defects. In group B (10 rabbits), the MSCs cultivated with chondrogenic differentiation medium was grafted into the defects. In group C (8 rabbits), the defects were repaired with autologous osteochondral grafts as control. Specimens were harvested at 4th, 8th, 16th and 24th week post operation respectively, histological examination was performed and graded. Results For the MSCs cultivated with regular medium, the expression of mRNA for type Ⅰ collagen was found with RT-PCR, but no expression for Ⅱ collagen was found. For the induced MSCs, the expression of mRNA both for type Ⅰ and type Ⅱ collagen were found. The adhesion and growth of MSCs on the PLGA double-layer scaffold were well visualized with scanning electron microscopy, and some cells were found in the deep porotic area. For the specimens of group B, no significant difference was found comparing with normal cartilage at 24th week, and the specimens were defined as matured hyaline-like cartilage(4/6)with histological examination, superior to those specimens of group A (1/4). Conclusion The MSCs have osteogenic and chondrogenic potentiality. Combined with PLGA double-layer scaffold, it can be served as seeded cell to form tissue-engineered composite grafts, which can be used to repair osteochondral defects in rabbit models.