Abstract: Objective: To investigate whether Blebbistatin could regulate the distribution of CXC chemokine receptor 4 (CXCR4) in rat bone marrow mesenchymal stem cells and promote the migration of bone marrow mesenchymal stem cells (BMSCs). Methods: BMSCs were isolated from SD rats using the whole bone marrow adherence method and the cells were treated with Blebbistatin for 15, 30, 45 and 60 min. The expression of surface CXCR4 was detected by flow cytometry. Cell migration ability was tested by Transwell migration assay. Osteogenesis was induced then ALP activity was detected in the early stage of induction, and was confirmed by alizarin red staining when induction was completed. Results: The surface expression of CXCR4 of Blebbistatin-treated cells was significantly increased in a time-dependent manner (P<0.01). Cell migration efficiency of Blebbistatin-treated cells increased in 15, 30 and 60 min groups (P<0.01). During osteogenic induction, there was no significant difference in the ALP activity among the groups. A large number of calcified nodules were found in all the groups on the 21th day. Conclusion: Blebbistatin promoted the surface expression of CXCR4 in BMSCs and promoted the migration of BMSCs.

Key words: Bone marrow mesenchymal stem cells, Blebbistatin, CXC chemokine receptor type 4, Stromal cell-derived factor-1