Abstract: Objective:To investigate the effect of autophagy on the proliferation of osteoblasts induced by hypoxia. Methods：Preparation of cell hypoxia model by CoCl2 for LC3was detected by Western blot and immunofluorescence assay; autophagosome was detected by transmission electron microscope; MTT assay and flow cytometrywesr used to detect the effect of autophagy on cell proliferation respectively. Results：The expression of autophagosome double membrane forming protein LC3-II began to increase CoCl2 treatment 3h later, reached the highest value 6h later, and then decreased the expression level. The results of immunofluorescence showed that LC3 protein in cytoplasm was higher than that in the control group. Autophagosomes were detected in experimental group. Compared with the control group, the cell growth was inhibited by CoCl2, reached its peak 12h later, and then the inhibitory ability became weakened. The G1 phase ratio was higher and G2 phase ratio was less than the control group. Conclusion: Hypoxia up-regulates autophagy activity of osteoblasts for inhibiting cell proliferation

Key words: hypoxia, autophagy, osteoblasts, proliferation