Study of dynamic pressure to promote the angiogenesis of bone matrix

Abstract

Objective To observe the effects of dynamic pressure for the ability of endothelial progenitor cells (EPCs) to form blood vessels, when EPCs seeded into DBM with load. Methods Use the Ficoll density gradient centrifuge combined with difference-speed adherence screening method to separate MNCs from rat bone marrow. Identify the induced EPCs by means of immunohistochemistry and immunofluorescence. Through the organization of fixed, defatted, decalcified and other steps use of spine vertebral body,demineralized bone matrix (DBM) samples of pig were prepared in vitro. Divided scaffolds into two groups A and groups B. Induced EPCs were seeded into DBM. The cell-seeded scaffolds of groups A were dynamically loaded in compression using a sine wave at 1 Hz, 5% strain in the media-filled chamber for 4 h on days 5 of culture. and cell-seeded scaffolds of groups B were cultured directly without any load. Both of two groups were cultured two weeks. Then the ability of EPCs to form blood vessels was observed. Primer desig;Extract total RNA from cells with Trlzol; Reverse transcription reaction; PCR. Results Two groups of cells in HE staining and fluorescent staining showed the formation of vascular bundles. There were formation of blood vessels. It was obvious that the formation in group A was more than that in group B. Test the mRNA expression of vWF and Flk-1 during the EPCs differentiationby RT-PCR. Group A was significantly stronger than that of group B. Conclusion When DBM combines together with EPC, it has become organization engineering bone, then with press on it, the bone graft has been vascularized, so it has clinical application on the direction of repair bone defect. Key words: Pressure; Neovascularzation, physiologic; Tissue engineering