Objective To identify the differentially expressed genes of osteoblasts under the stimulation of mechano growth factor E peptide( MGF-Ct24E) and mechanical stress by microarray analysis. Methods Primary osteoblasts were cultured in vitro, which were subjected to mechanical stimulation(with the mechanical strain of 12% and frequency of 0.5 Hz) and MGF-Ct24E treatment(50 mg/L), respectively. The gene expression profiles were analysed by cDNA microarrys and quantitative PCR was used to validate the microarray data. ResultsCompared with the control group, 1 866 genes were found to have differentially expressed in the mechanical loading group, in which 1 113 genes were up-regulated, while 753 genes were down-regulated. 1 178 genes were found to have differentially expressed in the MGF-Ct24E group, in which 796 genes were up-regulated and 382 genes were down-regulated. GO analysis suggested that the gene expression profile of MGF-Ct24E group was consistent with that of the mechanical loading group and differentially expressed genes were mainly involved in cell proliferation and differentiation, response to mechanical stress and mechaotransduction. ConclusionsThe microarray analysis showed that MGF-Ct24E treatment had similar effects with the mechanical loading on the gene expression of osteoblasts, which might provide a novel approach to study the usage of MGF-Ct24E for treating bone repair in the absence of mechanical stimulation.