Abstract: Objective: To investigate the effects of bone morphogenetic protein7(BMP7) on biological properties of osteoblasts in high glucose circumstance. Methods: MC3T3-E1 Sub-clone 14 cells were cultured and divided into four groups according to the different culture medium:normal glucose concentration of 5.5 mmol/L;normal glucose concentration of 5.5 mmol/L and BMP7 (100 μg/L); high glucose concentration of 25 mmol/L;high glucose concentration of 25 mmol/L and BMP7(100 μg/L),respectively. The cell proliferation was measured by MTT assay 1d,3d,5d and 7d after exposure. The alkaline phosphatase (ALP) activity was used to detect the differentiation of MC3T3-E1 cells. The Alizarinred dye wasused to observe the number of calcium nodes at 21d. The F-actin cytoskeleton of MC3T3-E1 was stained with Rhodamine,then examined under a confocal laser scanning microscope 24h after exposure to BMP7. The mRNA expressions of ALP, osteocalcin(OCN) and Runx2 were quantified by real-time PCR(RT-qPCR) 48h after exposure to BMP7. Results: The MTT, ALP assays showed that high glucose(25mmol/L) inhibited MC3T3-E1 proliferation and ALP activity(P＜0.05),also decreased mRNA expression of ALP, OCN and Runx2,the addition of BMP7 significantly increased ALP, OCN and Runx2 expression. In the cells exposed to high glucose, F-actin cytosksleton started to change with disruptive structures. Conclusion: High glucose concentration significantly inhibited the proliferation andALP activity,destroyed F-actin cytoskeleton structure,and inhibited the expression of osteoblasticgene. BMP7 could promote the cell mineralization under such high glucose concentration environment.

Key words: Bone morphogenetic protein 7, Osteoblasts, High glucose, Cytoskeleton