Objective To observe the expression of Runx2 in osteoblasts in response to centrifugation in vitro and discuss the function of bone morphogenetic protein（BMP） signal transduction pathway in this course. Methods Cells were divided into four groups, group A, B, C and D, pretreated with DMEM containing 10% fetal bovine serum, 10% fetal bovine serum, 100 ng·mL-1 Noggin and 100 ng·mL-1 Noggin for 24 hours separately. 271×g centrifugation was loaded for 5 min to these groups except group A and C, other conditions were the same. The total RNA of each group were extracted, and reversed transcription to cDNA after 30 min. The expression of Runx2 in response to centrifugation in vitro was analyzed by quantitative real time PCR. Results The expression of Runx2 mRNA in group B was significantly higher than that in group A（P
