Ectopic Bone Formation Of Bone Marrow Mesenchymal Stem Cells Transfer Mediated By Human Bone Morphogenetic Protein-9 Gene In Rabbit

Objective hBMP-9 gene therapy combined with tissue-engineering techniques was explored to improve osteogenesis in an ectopic bone formation model in rabbits.Method Autologous rabbit MSCs were cultured and transfected with pEGFP-BMP-9 gene by lipofectamine, fluorescent microscope,Flow cytometer (FCM),ALP activity quantitative assay and Von Kossa's calcium nodus staninig were detected; PLGA was prepared and MSCs infected by BMP-9 gene with cationic liposome were seeded onto it. Scanning electronic microscopy as used to observe cell matrix interaction. The cells infected and non-infected were combined with PLGA to construct tissue-engineered bones respectively. They were further implanted into rabbits subcutaneously. Four and eight weeks after surgery, the implants were evaluated with X-rays photographs and histological staining.Result The transfection efficiency of MSCs infected by BMP-9 gene with cationic liposome detected by FCM was34.15%, the ALP activity of infected MSCs was higher than that of non-infected MSCs (p<0.05), the calcium nodus of MSCs formation of BMP-9 gene infected group were manifest larger than the non-infected group; PLGA prepared was a grid-like porous structure, with definite ductility and strength, and could be trimmed into different models. MSCs seeded onto PLGA showed high level of proliferation, and mass synthesis of cell matrix was observed with scanning electronic microscopy. In the ectopic bone formation model, four weeks after surgery, in the X-rays photographsthe can see bone tissue image formation of the experimental group, and the image became augmentation in eight weeks; the new bone area formed in the non-infected MSCs group was lower than the BMP-9 gene infected group (p<0.05). The ALP activity in the experiment side was obviously higher than that in the control side(p<0.05).Conclusion BMP-9 gene modified MSCs could enhance ectopic new bone formation in rabbits. These results indicated that the MSCs transfer mediated by rhBMP-9 gene with cationic liposome combine with PLGA might be suitable for bone tissue engineering applications.