Objective To determine the optimal conditions for CXCR4 upregulation by comparing the expression levels of chemokine(C-X-C motif)receptor 4(CXCR4)in MSCs cultured with varying concentrations of oxygen and hydrogen peroxide(H2O2).Methods MSCs were cultured with 0.1％,1％,or 3％O2 and 50 μmol/L H2O2 for different lengths of time(3,6,12,and 24 h).The mRNA and protein expressions of CXCR4 in MSCs were measured by real-time quantitative PCR(qPCR),Western blotting,and immunofluorescence staining.The viability and chemotactic ability of MSCs were measured using CCK-8,wound-healing and Transwell migration assays.Results Both hypoxia and H2O2 treatment were found to upregulate MSC expressions of CXCR4 to some extent.The mRNA and protein levels of CXCR4 were higher after 6-12 h of culture of MSCs with 3％O2,and significantly higher when treated with H2O2 for 6 h.Cell viability was significantly increased after culture with 3％O2 compared with the control group and both 3％O2 and H2O2 pretreatment could enhance chemotactic migration in MSCs.Conclusion Culture with 3％O2 and H2O2 pretreatment can upregulate CXCR4 expressions in MSCs and enhance migration in cells,with superior effects observed with 3％O2.Therefore,treatment with 3％O2 represents the best choice for upregulating the chemotactic ability of MSCs.