Abstract: Objective To investigate the effects of simvastatin on osteoblast differentiated rat bone marrow stromal cells(BMSCs), as well as the differently expressed genes associated with osteogenesis of the BMSCs during this process. Methods Bone marrow stromal cells from the femurs and tibias of 6-week old rats were cultured in vitro, three days later the cells were treated with simvastatin(1×10-7mol/L)(group SIM) or vehicle(group V). Alkaline phosphatase activity was assessed at 14th day, the following assays were performed at 21th day: Von Kossa staining for observing extracellular matrix mineralization; total RNA was extracted for detecting the gene expression profiles by Oligonucleotides microarray chip and were confirmed by real-time quantitative RT-PCR. Results 1.Cells in SIM showed significantly higher ALP activity and ability of extracellular matrix mineralization compared with those of group V;（p<0.05） 2.Oligonucleotides microarray chip analysis showed that 678 genes out of 22,575 rat genes had differential expression (≥2 fold or ≤0.5 fold), including genes known to be related to osteogenesis, such as , ALPl、TGFβ1、OCN、DLX5、Axin2、BMP-2、IBSP、MMP13, etc. Conclusion Simvastatin could promote the osteogenic differentiation of BMSCs in vitro, many genes associated with osteogenesis may participate in this process.

Key words: Simvastatin, Oligonucleotide microarray, Gene expression, Bone marrow stromal cells, Osteoblast