Effects of basic fibroblast growth factor on cartilage to bone: Time-course histological analysis of in vivo cartilage formation from polydactyly-derived chondrocytes.

INTRODUCTION: Cartilage tissue is important in the human body as a ubiquitous connective tissue. However, information on the limits of chondrocyte growth and the effects of basic FGF (bFGF) in vivo is scarce. This study aims to investigate the effects of bFGF on the growth rate, cytology, and morphology of implanted cultured epiphyseal cartilage-derived chondrocytes into NOD/Shi-scid IL-2Rγnull mice (NOG mice).

METHODS: Chondrocytes were isolated from the epiphyseal cartilage derived from the digits of polydactyly patients and were cultivated in a medium supplemented with bFGF (bFGF-treated cells) and without bFGF (bFGF-untreated cells). These cultivated cells were subcutaneously implanted into the backs of NOG mice.

RESULTS: bFGF-treated cells exhibited a higher growth rate than bFGF-untreated cells. Cartilage was formed after two weeks of implantation. The cartilages generated by bFGF-treated cells (denoted as "BT-cartilage" hereafter) were larger in size and heavier in weight than those cartilages generated by bFGF-untreated cells (denoted as "BUT-cartilage" hereafter). BT-cartilage grew exponentially after 10 weeks.

CONCLUSIONS: From these results, bFGF-treated cells exhibited increased ability for both proliferation and differentiation compared to bFGF-untreated cells. The results of this study may lead to the generation of new alternative therapies for bone and cartilage through the use of epiphyseal chondrocytes.