MiR-31 Improves Spinal Cord Injury In Mice By Promoting The Migration Of Bone Marrow Mesenchymal Stem Cells

Objective: Stem cell transplantation therapy is a potential approach for the repair of spinal cord injuries and other neurodegenerative diseases,but the effectiveness of cell transplantation is hampered by the low rate of targeted migration of cells to the area of injury.The aim of this study was to investigate the effects of miR-31 on the migration of bone marrow mesenchymal stem cells and the regulation of MMP-2 and CXCR4 expression in vitro and in vivo.Methods: The eGFP BMSCs were extracted and cultured and identified.After cell transfection,the experiments were divided into control,miR-31 agomir and miR-31 antagomir groups.The proliferation was analyzed by CCK-8 and flow cytometry;the migration of cells in vitro was analyzed by Wound-healing assay and Transwell assay;the expression of MMP-2 and CXCR4 in vitro was evaluated by Western blot.Animal models of spinal cord injury in mice were prepared by the Impact method,and cells were transplanted(3 groups,n=12/group).The inflammatory factors associated with spinal cord injury were detected by ELISA;the BMS score was used to evaluate the functional recovery of the mouse spinal cord;frozen sections were used to analyze the migration ability of cells in vivo;the expression of MMP-2 and CXCR4 in vivo was evaluated by Western blot and immunohistochemical staining.Results: In vitro experiments showed that the miR-31 agomir group had enhanced cell proliferation(P<0.05,P<0.001),promoted cell migration(P(27)0.001),and upregulated CXCR4 and MMP-2 protein expression(P<0.01,P(27)0.001)compared with the control group.The results of in vivo experiments showed that the expression of pro-inflammatory factors was reduced after cell transplantation treatment.The miR-31 agomir group had enhanced cell-targeted migration ability(P(27)0.001),improved the function of damaged tissues(P(27)0.001),and upregulated CXCR4 and MMP-2 expression compared to the control group(P(27)0.001).Conclusion: The experiment demonstrated that miR-31 can promote the migration of bone marrow mesenchymal stem cells and that miR-31 can repair and improve the function of damaged tissues in spinal cord injury.