The role of recombinant human bone morphogenetic protein-2 in PLGA capsules at an extraskeletal site of the rat

Bone morphogenetic protein-2 (BMP-2) is a member of the transforming growth factor-beta (TGF-beta ) superfamily and has strong bone-inductive activity in vivo. To examine the role of BMP-2 in an extraskeletal site of rat usin g a controlled release system of peptides, we entapsulated the recombinant human BMP-2 (rhBMP-2) with poly(DL-lactide-co-glycolide) (PLGA) and implant ed the rh-BMP-2/PLGA capsules in the subcutaneous area of rats. Upon histoc hemical examination, it was found that bone-inducing cells having alkaline phosphatase (ALP) activity appeared around the capsules by the suitably rel eased rhBMP-2. in addition, the temporal histological examination showed th at direct bone formation without cartilage occurred in the process of this ectopic bone induction. These data indicate that the role of rhBMP-2 in the extraskeletal site of rats is to induce the differentiation of mesenchymal cells into the osteoblasts. (C) 1999 John Wiley & Sons, Inc.