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Objective: To evaluate the osteogenic efficacy of mouse bone marrow stromal cells (mBMSC) transfected with bone morphogenetic protein 2 (BMP2) and vascular endothelial growth factor 165 (VEGF(165)) genes., Methods: pIRES-BMP2-VEGF(165) plasmid DNA was introduced into the mBMSC using a liposome-mediated method. The expression of BMP2 and VEGF(165) genes was assessed by reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemical analysis. Transfected cells were injected into the thigh muscle pouches of four nude mice. The osteoinductivity activity of the transfected cells was evaluated by radiographic and histological analysis at 4 weeks after injection., Results: The mRNA and proteins of both BMP2 and VEGF(165) were successfully expressed in mBMSC as confirmed by RT-PCR and immunohistochemical analysis. Ectopically formed bone tissue was clearly observed at 4 weeks after cell injection in the thigh muscle pouches of the nude mice., Conclusion: mBMSC transfected with BMP2 and VEGF(165) genes can induce ectopic osteogenesis., (© 2009 Tianjin Hospital and Blackwell Publishing Asia Pty Ltd.)

Background: Nanobone putty is an injectable and bioresorbable bone substitute. The neutral-pH putty resembles hard bone tissue, does not contain polymers or plasticizers, and is self-setting and nearly isothermic, properties which are helpful for the adhesion, proliferation, and function of bone cells. The aim of this study was to investigate the osteogenic potential of human bone morphogenetic protein 2 (hBMP2) gene activated nanobone putty in inducing ectopic bone formation, and the effects of the hBMP2 gene activated nanobone putty on repairing bone defects., Methods: Twenty four Kunming mice were randomly divided into two groups. The nanobone putty + hBMP2 plasmid was injected into the right thigh muscle pouches of the mice (experiment side). The nanobone putty + blank plasmid or nanobone putty was injected into the left thigh muscle pouches of the group 1 (control side 1) or group 2 (control side 2), respectively. The effects of ectopic bone formation were evaluated by radiography, histology, and molecular biology analysis at 2 and 4 weeks after operation. Bilateral 15 mm radial defects were made in forty-eight rabbits. These rabbits were randomly divided into three groups: Group A, nanobone putty + hBMP2 plasmid; Group B, putty + blank plasmid; Group C, nanobone putty only. Six rabbits with left radial defects served as blank controls. The effect of bone repairing was evaluated by radiography, histology, molecular biology, and biomechanical analysis at 4, 8, and 12 weeks after operation., Results: The tissue from the experimental side of the mice expressed hBMP2. Obvious cartilage and island-distributed immature bone formation in implants of the experiment side were observed at 2 weeks after operation, and massive mature bone observed at 4 weeks. No bone formation was observed in the control side of the mice. The ALP activity in the experiment side of the mice was higher than that in the control side. The tissue of Group A rabbits expressed hBMP2 protein and higher ALP level. The new bone formation rate and antibending strength of group A was significantly higher than those of group B and C. The defects in blank control were not healed., Conclusions: The hBMP2 gene activated nanobone putty exhibited osteoinductive ability, and had a better bone defect repair capability than that of nanobone putty only.

Objectives: To examine the gene expression profile of bone morphogenetic protein 2 (BMP-2) and vascular endothelial growth factor (VEGF) during entochondrostosis of mice and explore the expression rules and effects between BMP-2 and VEGF, and to detect the expression of VEGF in BMP-2 induced entochondrostosis in vivo., Methods: cDNA microarray technique with 34,000 genes was used to analyze the gene expression profiles during entochondrostosis in the limbs of mice embryo from E10 to E14. Pathway analysis of BMP-2 and VEGF was performed with GCOS1.2 software. An experimental model of femoral muscular pouch in 20 mice was adopted. The expression of VEGF was examined by in situ hybridization method and immunohistochemical method in BMP-2 induced entochondrostosis in vivo., Results: The expression signals of VEGF mRNA and VEGF appeared in cytoplasm during condensation of mesenchymal cell. As the mesenchymal cells differentiated into precartilage, the expression signals decreased in mesenchymal cells, but increased in chondrocytes and kept getting denser in the process of cartilage maturity. The peak expression of VEGF mRNA and VEGF in the experimental group appeared on the 14th day, accompanied by numerous hypertrophic chondrocytes. When mature cartilage calcified and new bone trabecula formed, the expression of VEGF mRNA and VEGF decreased in chondrocytes, but still expressed moderately in the osteoblasts and osteocytes., Conclusions: The finding reveals a complex pattern of gene coexpression of BMP-2 and VEGF during the critical period of entochondrostosis. It's feasible for the clinical application of BMP-2 in orthopedics.