Effect of phosphorus on the osteogenesis of human osteoblasts
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Bioactive glasses, which are mainly composed of silicon, calcium, and phosphorous have been frequently used as synthetic bone graft materials. However, the effect of osteogenesis by ions released from bioactive glass is still unknown. In this study, effects of phosphoric ion on cell attachment efficiency, cell proliferation, osteocalcin expression, alkaline phosphatase (ALP) activity, and mineralization of human osteoblasts were tested in vitro. The second passage of human osteoblast-like cells, derived from healthy human alveolar bone, was used in this study. Cells were cultured in media supplemented with additional phosphorous ions at 6, 12, 25, 50, 100 ppm for 12 and 20 days. Culture media without phosphoric ion supplement but which already contained a physiologic range of phosphoric ions was used for control. Culture medium with Vit D3 supplement was used for all culture for 48 hours. Cells were screened for osteoblast phenotype prior to all experiments. The culture medium was observed for pH change. Cell attachment and cell proliferation were determined by measuring the optical density of crystal violet dye in fixed cultured cells, ALP activity was determined by optical density measurement of pNP mixture in fixed cultured cells. Mineralization was determined by applying Alizarin red S stain to the calcium deposits of cultures. Osteocalcin expression was determined by the measurement of 125[superscript]I -labeled antibody in extracted culture media. All data were calibrated on a per 10 ^ 5cells basis and tested by ANOVA and Tukey statistical analysis. Mean pH value of culture medium was decreased during the culture period. Cell attachment efficiency was decreased in culture medium with phosphorous ion concentrations higher than 50 ppm (P=0.0018), and 25 ppm phosphoric ion supplemented culture media increased cell proliferation rate significantly at 12 days (p[less than]0.0001); 6 ppm phosphorous ion significantly increased osteocalcin expression and mineralization at 1 2 days (p[less than]0.0001). This in vitro study demonstrated an important role of phosphorous ion in effecting osteogenesis of normal human osteoblast cultures. Future study of combinations of silicon, calcium and phosphorous is recommended to clarify the effect of these molecules in osteogenesis at the cellular level.
PLEASE NOTE: This work is protected by copyright. Downloading is restricted to the BU community: please click Download and log in with a valid BU account to access. If you are the author of this work and would like to make it publicly available, please contact firstname.lastname@example.org.Thesis (M.S.D.)--Boston University, Henry M. Goldman School of Dental Medicine, 2002 (Prosthodontics).Includes bibliographical references (leaves 88-101).
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