The Role Of Angiopoietin1 On Osteocalsts In Orthodontic Tooth Movement

This study aimed to investigate the expression pattern of Angiopoietin-1 (Ang1) in the pressure side of periodontal tissues during orthodontic tooth movement (OTM) and its regulatory effects on osteoclast precursor cells and osteoclastogenesis. A total of 9 three-month-old male Sprague-Dawley (SD) rats were used in this study . A Ni-Ti spring coil was applied to the first molar of the rat to induce mesial tooth movement for 7 and 14 days and the sample operation without applying force were used as the control group. Immunofluorescence staining was performed to assess the expression pattern of Ang1 in the periodontal tissue on the pressure side. In vitro, mouse monocyte-macrophage RAW264.7 cells were cultured and subjected to hypoxia induction (using CoCl₂) or RANKL-induced osteoclast differentiation. The mRNA expression of Ang1 was analyzed by RT-qPCR, and Ang1 protein expression was detected via immunofluorescence staining. 1.Immunofluorescence staining revealed that the Ang1 expression on the OTM compression side was significantly downregulated compared to the control group; 2.CoCl₂-induced chemical hypoxia significantly downregulated Ang1 expression in osteoclast precursor cells;3.Exogenous recombinant Ang1 protein suppressed the relative mRNA expression of osteoclast markers and significantly reduced osteoclast formation. Ang1 is downregulated on the compression side of the OTM and its mechanisms could be via negatively regulating the formation of the osteoclasts during OTM.