Repair of osteochondral defects with adipose stem cells and a dual growth factor-releasing scaffold in rabbits

The purpose of this work was to evaluate the in vivo effectiveness of a TGF-β₂ and bone morphogenetic protein (BMP)-7-immobilized porous polycaprolactone (PCL)/F127 scaffold to enhance the healing of cartilage defect. An osteochondral defect was created on the patellar groove of the right distal femur of 12 rabbits and managed by one of the following methods: filling it with the scaffold only (Group I); the scaffold seeded with adipose stem cells (ASCs) (Group II); a TGF-β₂ and BMP-7-immobilized scaffold (Group III); and a TGF-β₂ and BMP-7-immobilized scaffold seeded with ASCs (Group IV). Each group had three rabbits. Nine weeks after the implantation, the implanted scaffolds were filled with yellowish, dense tissue, and had distinct margins with adjacent normal cartilage. The histological findings showed infiltration of foreign-body giant cells and blood vessel, more prominently in Groups III and IV. The presence of growth factor significantly increased the ICRS Macroscopic Score (p 5 0.045) while the presence of ASC did not. The ICRS Visual Histological Score was not significantly affected by the presence of either growth factors or ASCs, showing similar values in all groups. In conclusion, the use of TGF-β² and BMP-7-immobilized PCL/F127 scaffolds improved gross appearances of the osteochondral defects while not actually leading to better histological results and induced a greater degree of foreign body reaction.