ABSTRACT
ObjectiveTo investigate the molecular mechanism of prostaglandins E2 ( PGE2 ) in promoting bone formation by detecting the changes of gene expression profiles of MC3T3-E1 osteoblasts treated with PGE2. MethodsThe genes with differential expression in MC3T3-E1 osteoblasts treated with 10 μmol/L PGE2 for 30 minutes were performed by gene chip technology. Several major genes during bone regeneration were selected for Western blot analysis. ResultsAfter co-culture of MC3T3-E1 cells with PGE2 at concentration of 10 μmol/L for 30 min, 276 genes were up-regulated, including bone regeneration related MMD (monocyte to macrophage differentiation associated), NR4A2 (nuclear receptor subfamily 4, group A, member 2), BMP-7 ( bone morphogenetic protein-7), POSTN ( periostin, osteoblast specific factor) and catenin (cadherin-associated protein) genes; and 168 genes were down-regulated,including bone regeneration related Idl ,2,3 ( inhibitor of DNA binding 1,2,3 ) genes. Western blot analysis indicated that the expressions of nuclear factor (NF)-κB p65 and BMP-7 protein in the osteoblasts treated with 10 μmol/l PGE2 were apparently higher ( P ＜ 0. Ol ) than that of the controls, whereas the ld2 expression decreased (P ＜0. O1 ) under the same conditions, which was almost the same as the results of gene chip technology. ConclusionsWith the results of gene chip and Western blot, it can be speculated that the PGE 2 firstly activates the nuclear receptor NR4A2 and then the nuclear transcription factor NF-κB, induces the changes of the downstream gene BMP-7 and Id2 expression and finally results in the differentiation of the osteoblasts and promote the bone regeneration.