ENHANCED VASCULARIZATION AND TISSUE GRANULATION BY BASIC FIBROBLAST GROWTH-FACTOR IMPREGNATED IN GELATIN HYDROGELS

Basic fibroblast growth factor (bFGF) was impregnated through polyion complexation into biodegradable hydrogels prepared by crosslinking of acidic gelatin with the isoelectric point of 4.9. Release experiments demonstrated not to release bFGF from the gelatin hydrogel under the in vitro non-degradation conditions. The hydrogels were degraded with time following their subcutaneous implantation on the mouse back and the period of in vivo degradation varied depending on the water content of hydrogels. The gelatin hydrogels containing bFGF strongly induced neovascularization and tissue granulation around the implantation site, whereas subcutaneous injection of bFGF in solution form did not increase the amount of tissue hemoglobin and the wet weight of tissue. The bFGF-impregnated gelatin hydrogel of lower water content retained the vascularization effect for a longer period. It was concluded that bFGF was released from gelatin hydrogel as a result of their in vivo degradation, leading to more efficient induction of neovascularization and tissue granulation than free bFGF without impregnation in the hydrogel.