The Influences of β-Glucan Associated with BMP-7 on MC3T3-E1 Proliferation and Osteogenic Differentiation

beta-glucan, an immunomodulator, can selectively enhance the immunobiological activities of neutrophils and macrophages without stimulating proinflammatory cytokine production. Biologic response modifiers, like beta-glucan, will modulate immunity, modify neoplastic disease and increase resistance to microbial challenge. Therefore, beta-glucan polymers can be applied in bone induction and regeneration model and have a possibility of association with bone morphogenetic protein (BMP) because of tissue-regenerative and antimicrobial effects of those polymers. In this report, we studied an E. coli expression system for BMP-7 production and the biological activities of beta-glucan associated with BMP-7. The proliferation of MC3T3-E1 osteoblastic cells was enhanced by treatment with Aureobasidium beta-glucan, while neither mushroom beta-glucan nor barley beta-glucan increased the cell proliferation. Mushroom beta-glucan alone or associated with BMP-7 increased alkaline phosphatase (ALP) activity of MC3T3-E1 cells, one of the osteoblast phenotype markers, but the other beta-glucans did not affect ALP activity of the cells. In mineralization assay, a highly significant increase in nodular staining was observed in cultures treated with both mushroom and Aureobasidium beta-glucans in the presence of BMP-7 compared with nontreated controls, while barley beta-glucan showed a significant decrease in nodule number compared with cultures treated only with BMP-7.