| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2004: ¥600,000 (Direct Cost: ¥600,000)
Fiscal Year 2003: ¥3,000,000 (Direct Cost: ¥3,000,000)
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| Research Abstract |
This study evaluated the effectiveness of b-FGF impregnated in gelatin microspheres to achieve slow growth factor release for augmenting the in vivo chondrogenic response. Whereas ^<125>I-labeled b-FGF injected in solution showed rapid in vivo clearance from the injection site (only 3% residual after 24 hours), when incorporated into gelatin microspheres, 44% and 18% of the b-FGF remained at 3 and 14 days, respectively. Canine chondrocytes were isolated and grown in vitro onto ear-shaped poly-lactide/capro-lactone copolymers for one week, then implanted into the dorsal subcutaneous tissue of nude mice ; implants contained b-FGF either in free solution or in gelatin microspheres. A third group underwent pre-injection of b-FGF in gelatin microspheres four days before chondrocyte-copolymer implantation. The implants with b-FGF-incorporated microspheres showed the greatest chondrogenic characteristics at 5 and 10 weeks postoperatively : good shape and biomechanical trait retention, strong (histologic) metachromasia, rich vascularization of surrounding tissues, and increased gene expression for type II collagen (cartilage marker) and factor VIII-related antigen (vascular marker). In the case of implant site pre-administration with b-FGF-impregnated microspheres, the implant architecture was not maintained as well, and reduced vascularization and metachromasia was also apparent. In conclusion, these findings indicate that a sustained release of b-FOE augments neovascularization and chondrogenesis in a tissue-engineered cartilage construct.
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