ABSTRACT
The objective of this study was to induce bone formation from immature muscular tissue (IMT) in vitro, using bone morphogenetic proteins (BMPs) as a cytokine source and an expanded polytetrafluoroethylene (ePTFE) scaffold. In addition, cultured IMTs were implanted subcutaneously into Sprague-Dawley (SD) rats to determine their in vivo ossification potential. BMPs, extracted from bovine cortical bones, were applied to embryonic SD rat IMT cultures, before 2 weeks culture on ePTFE scaffolds. Osteoblast-like cells and osteoid tissues were partially identified by hematoxylin-eosin staining 2 weeks after culture. Collagen type I (Col-I), osteopontin (OP), and osteocalcin (OC) were detected in the osteoid tissues by immunohistochemical staining. OC gene expression remained low, but OP and Col-I were upregulated during the culture period. In vivo implanted IMTs showed slight radiopacity 1 week after implantation and strong radiopacity 2 and 3 weeks after implantation. One week after implantation, migration of numerous capillaries was observed and ossification was detected after 2 weeks by histological observation. These results suggest that IMTs are able to differentiate into bone-like tissue in vitro, with an ossification potential after implantation in vivo.
