Scaffold-free cartilage fabrication system using passaged porcine chondrocytes and basic fibroblast growth factor

The scaffold-free cartilage fabrication system we have reported previously for human application with nonpassaged cells has a big limitation in securing the enough cell number. Therefore, autologous chondrocytes from small biopsy of cartilage tissue inevitably have to be expanded through multiple passages, which result in poor engineered cartilage in terms of quality and quantity. This study applied basic fibroblast growth factor (bFGF) to overcome the limitation and produce an engineered cartilage tissue with clinically applicable size and quality. Porcine articular chondrocytes were expanded until passage 2 in the absence or presence of 5 ng/mL bFGF, and then subjected to the two-stage scaffold-free cultures for 21 days again in the absence or presence of 5 ng/mL bFGF. The fabrication of cartilage tissues was evaluated along with time in comparison with the constructs from unpassaged chondrocytes. Expansion of chondrocytes in the presence of bFGF increased accumulation of cartilage extracellular matrices and resultantly fabricated the larger size of cartilage tissues in the subsequent stages, being comparable to those of unpassaged cells. In contrast, bFGF showed no positive, but adverse, effects on the cartilage tissue formation, when treated additionally during the scaffold-free fabrication stages. These results suggested that use of bFGF during the expansion stage of chondrocytes could overcome the limitation of previous two-stage scaffold-free cartilage fabrication system, and provided a novel three-stage system to construct a clinically applicable quality of cartilage tissues.