TISSUE ENGINEERING STUDIES ON BONE FORMATION USING NEW EXTRACELLULAR MATRIX MATERIAL / 解放军医学杂志

To design and manufacture a new bone matrix material (NBM) composed of both organic and inorganic materials for bone tissue engineering, the osteogenic potential of NBM combined with osteoblasts was studied in vitro and in vivo. Osteoblasts from bone marrow stromal cells of New Zealand rabbit were cultured with NBM in vitro , then the materials combined with osteoblasts were implanted into the skeletal muscles of rabbits. The osteogenic potential of NBM was evaluated using contrast microscope, scan electromicroscope and histological examination. Osteoblasts could attach and proliferate well in the NBM, secrecting lots of extracellular matrix, while in vivo experiment of the NBM in osteoblasts group showed that a large number of lymphacytes and phagocytes invaded into the inner of the material in the rabbit skeletal muscle beds after 4 weeks of implantation, no new bone formation was observed after 8 weeks. The different osteogenic potential expressed by NBM between in vitro and in vivo may be due to the immunogenity of NBM which causes cellular immunoreaction to destroy the osteogenic environment. More attention should be paid to the immunoreaction problem in tissue engineering between the host and organic inorganic composite materials.

HUMAN BONE MORPHOGENETIC PROTEIN 7 EXPRESSION IN RABBIT BONE MARROW STEM CELL TRANSFERRED BY RETROVIRAL VECTOR MEDIATED hBMP_7 GENE / 解放军医学杂志

The human bone morphogenetic protein 7 (hBMP 7) gene was reconstructed in retroviral vector and transferred into incasing cells PT67 by liposome mediated method.The clones of the cells transferred with BMP 7 were selected by G418, and targeted rabbit bone marrow stem cells were infected with the virus granules which secreted from PT67 cells and also selected by G418. The mRNA and protein of BMP 7 gene in transferred cells were analyzed with hybridization in situ and immunohistochemistry. BMP 7 retrovirus vetor was successfully reconstructed. Cells transferred by PLNCX 2 hBMP 7 expressed abundant human BMP 7 mRNA and protein in the cytoplasm. However positive findings were not found in those cells that were not transferred. It may be used to increase the osteogenic capability of BMSc in the study of bone tissue engineering.