Effect of basic fibroblast growth factor on cartilage regeneration in chondrocyte-seeded collagen sponge scaffold.

A chondrocyte-collagen composite was prepared in an attempt to regenerate cartilage by its subcutaneous implantation in nude mouse. When the composite was impregnated with basic fibroblast growth factor (bFGF) prior to implantation, regeneration of the cartilage tissue was remarkably accelerated. Histological staining of the implanted composites with Safranin O-fast green revealed that the cells incorporated in the composites exhibited their phenotype and formed a new matured cartilage. A thin layer of fibrous capsule was observed surrounding the implanted composite and the inflammatory response of the host to the implant was mild. Specific proteoglycans were accumulated in the composite even 1 week after implantation. At 2 weeks after implantation, the chondrocytes regenerated the cartilage tissue, although still immature, but at 4 weeks almost all of the chondrocytes transferred to the mature stage. Conversely, such mature cartilage tissue was not noticed up to 4 weeks after implantation if the collagen scaffold was not impregnated with bFGF. Moreover, the mature area was limited to only a small fraction of the implanted composite, unless bFGF was incorporated in it.