Study on the Mechanism of SIRT1 Toregulates Osteoblast Differentiation Through the PI3K/AKT Pathway
1.Department of Joint surgery，Xi'an Honghui Hospital
2.Shanxi University of Traditional Chinese Medicine
3.First Affiliated Hospital of Xi'an Jiaotong University
Abstract：Objective To studying the interaction between the SIRT1 gene and the PI3K-AKT pathway and investigate the effect of SIRT1 on osteoblast differentiation. Methods Osteoblasts were extracted from the skull of Sprague Dawley rats and cultured for 3～4 passages.Then Cells were randomized into control group，resveratrol group and resveratrol + EX-527 group.Cell Counting Kit-8 (CCK-8) was used to determine the cytotoxicity of resveratrol and EX-527.Alkaline phosphatase (ALP) and alizarin red S staining were used to detect ALP levels and calcium nodules，respectively.Immunohistochemistry was used to observe the production of type I collagen to determine the differentiation of cells.The expression of SIRT1，Runt-related transcription factor 2 (RUNX2)，Osteopontin (OPN) and the phosphorylation levels of phosphatidylinositol 3 kinase(PI3K)andprotein kinaseB(AKT).Results Resveratrol and EX-527 had no effect on cell proliferation (P＞0.05).ALP level and calcium nodules increased significantly after addition of resveratrol，but decreased significantly after addition of EX-527.The amont of Type I collagen were up-regulated because of the resveratrol.The expression of RUNX2 and OPN in osteoblast increased with the increase of SIRT1 expression (P＜0.01 or P＜0.001).When SIRT1 was inhibited，the protein expression of related factors also decreased (P＜0.001).Concurrently，the phosphorylated levels of PI3K and AKT also showed SIRT1-dependent up-regulation and down-regulation (P＜0.05 or P＜0.001).Conclusion The effect of SIRT1 on rat osteoblast differentiation may be mediated through the PI3K-AKT pathway.
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