Osteogenesis activity in site of bone nonunion

Abstract

Objective To investigate expressions of BMP and decorin at the broken ends of bone nonunion after fracture and effects of percutaneous injection of exogenous BMP and decorin, alone or in combination, on treatment of nonunion.Methods Radial nonunion models were made in rabbits.Changes in tissue components at broken ends of the fractured bone were observed through microscopy, radiology and histology.The expressions of BMP and decorin were detected by immunohistochemistry, real-time PCR and Westem-Blot.Fibrin sealant(FS)was adopted for percutaneous injections of exogenous BMP and decorin, alone or in combination, into the bone nonunion sites.Ossification in the area of nonunion was observed by 3D CT 4 weeks after the injection.Results In areas of bone nonunion, the active cells that could differentiate into osteoblasts obviously diminished and the expressions of BMP and decorin, compared with those in the normal bone, decreased obviously(P<0.05).Injection of both BMP and decorin were more effective than injection of either of them alone in treatment of nonunion.Conclusions Because of an obvious decrease of BMP and decorin, local tissues in bone nonunion tend to show less anti-fibrosis and ossification abilities.Therefore, a combined injection of exogenous BMP and decorin can promote healing of the bone nonunion. Key words: Fractures, ununited; bone morphogenetic proteins; Ribonucleoproteins; Osteoblasts