Influence of VEGF/BMP-2 on the proliferation and osteogenetic differentiation of rat bone mesenchymal stem cells on PLGA/gelatin composite scaffold

G. An, W.-B. Zhang, D.-K. Ma, B. Lu, G.-J. Wei, Y. Guang, C.-H. Ru, Y.-S. Wang

Department of Orthopedics, The 1st Affiliated Hospital of Harbin Medical University, Harbin, China. WYS1975@163.com

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• Orthopedics

OBJECTIVE: To investigate the influence of VEGF/BMP-2 on the proliferation and osteogenic differentiation of rat bone mesenchymal stem cells BMSCs) on PLGA/gelatin composite scaffold.

MATERIALS AND METHODS: Randomly-oriented nanofibers with different ratios of Poly Lactic-co-Glycolic Acid (PLGA)/gelatin were produced through electrospinning. The mixture of nanofibers and BMSCs was pipetted onto the surface of the scaffolds, and BMSCs/PLGA/gelatin composite was obtained. The surface morphology, chemical structure, hydrophilicity and mechanical property of PLGA/gelatin nanofibers were revealed by scanning electron microscope. In vitro release kinetics of bone morphogenetic protein (BMP-2) and vascular endothelial growth factor (VEGF) were studied using ELISA kits. The cell adhesion, growth and proliferation of BMSCs on scaffolds were observed by scanning electron microscopy. The CCK-8 assay was used to evaluate the effects of VEGF/BMP-2 slow release system on the proliferation of BMSCs on scaffolds. RT-PCR was used to examine the activities of alkaline phosphatase (ALP), runt-related transcription factor 2 (RUNX-2), and osteocalcin (OCN).

RESULTS: In each group of cells in the in-vitro experiment, through electron microscope scanning, fiber scaffolds were interconnected three-dimensional reticular structure, BMSCs firmly attached to the fiber surface and internal stent, cells experienced a long spindle, polygon change, and branch-like protrusions on the cell surface were connected. Under the electron microscope, cell proliferation curve and osteogenesis markers (ALP, RUNX-2, OCN) expression in the dual factor group on cell adhesion, proliferation and differentiation were much better than those of blank control group and single factor groups.

CONCLUSIONS: In the successfully constructed gelatin/PLGA nanofiber scaffold, VEGF and BMP-2 can be sequentially released, during which VEGF and BMP-2 can promote the adhesion, proliferation, and differentiation of BMSCs.

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