Preparation of gelatin microspheres encapsulated with bFGF for therapeutic angiogenesis in a canine ischemic hind limb

Abstract

There is urgent need for the treatment of limb ischemia. In order to avoid the risk of genetic materials or injury in collection of implanted cells, a basic fibroblast growth factor (bFGF) sustained release system using cross-linked gelatin microspheres was developed for therapeutic angiogenesis. In this study, gelatin microspheres (MSs) and the complex of MSs and bFGF (MSs-bFGF) were prepared. MSs and MSs-bFGF were analyzed for morphology, particle size, in vitro bFGF release and the bioactivity of the released medium. MSs-bFGF was intramuscularly implanted into the ischemic hind limb of a dog and free bFGF, empty MSs and untreated animals were used as controls. Histological examination was performed for angiogenesis evaluation. After immersion in an aqueous solution, the un-cross-linked MSs became deformed and adhered together. The cross-linked MSs showed a more stable character both in vivo and in vitro. The bFGF released from MSs remained bioactive. The histological examination indicated that the densities of micro-vessels in the MSs-bFGF-treated hind limb muscle were significantly greater than that in the untreated control, free bFGF and empty MSs groups. The MSs-bFGF sustained release system was a simple, safe and effective way to achieve therapeutic angiogenesis in an ischemic limb.