RESUMEN
AIM:To study the influence of bone marrow mesenchymol stem cell-drived exosomes(BMSC-exo-somes)on hindlimb activity,and the numbers of reactive astrocytes and residual neurons in spinal cord injury(SCI)rats. METHODS:BMSCs were cultured using the whole bone marrow adherent culture method and surface markers CD 90 and CD34 were verified by flow cytometry.Exosomes were isolated by ultracentrifugation and the morphology of exosomes was observed under transmission electron microscope.The protein markers CD63 and CD9 were verified by Western blot.After exosomes were applied to SCI rats,the Basso,Beattie and Bresnahan locomotor rating scale score,the Nissl staining of the lesion site,and the numbers of reactive astrocytes and residual neurons were assessed at various time points.RESULTS:Transmission electron microscopic observation revealed the presence of saucer -shaped vesicles.BMSC-exosomes were found to express high levels of CD63 and CD9.Compared with injury group,significant improvement of hindlimb activity scores from day 14 after injury in treatment group was observed(P<0.05),and less reactive astrocytes and more residual neu-rons from day 7 after injury were also observed(P<0.05).CONCLUSION:BMSC-exosomes inhibit reactive astrocytes and death of neurons,and improve hindlimb activity in the rats after SCI.