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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.
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<p><b>OBJECTIVE</b>To screen out differentially expressed microRNAs (miRNAs) in the plasma of children with methylmalonic acidemia (MMA), to determine the expression of miR-9-1 in plasma and to preliminarily evaluate the significance of miR-9-1 as a biomarker in MMA.</p><p><b>METHODS</b>Plasma was obtained from 17 MMA children, 10 hyperhomocysteinemia (HHcy) children without MMA (HHcy group), and 10 normal controls. Of 17 MMA children, 12 had HHcy (MMA+HHcy group), and 5 had no HHcy (MMA group). The differentially expressed miRNAs were screened out by miRNA microarray. Differentially expressed miR-9-1 was selected, and plasma miR-9-1 levels were determined by RT-PCR. Urine was collected from MMA patients who received vitamin B12 treatment, and plasma miR-9-1 levels were determined by RT-PCR after treatment.</p><p><b>RESULTS</b>The miRNA microarray analysis showed that 26 miRNAs were differentially expressed, among which 16 miRNAs (including miR-9-1) were down-regulated over 2 times, while 10 miRNAs were up-regulated over 2 times. The MMA+HHcy , MMA and HHcy groups had significantly down-regulated miR-9-1 compared with the normal control group (P<0.01). The patients who showed a good response to vitamin B12 treatment had significantly increased plasma miR-9-1 levels, without significant difference compared with the normal control group.</p><p><b>CONCLUSIONS</b>Plasma miR-9-1 is significantly down-regulated in MMA patients, but it is significantly up-regulated after vitamin B12 treatment, suggesting that miR-9-1 may act as a biomarker in monitoring the progression of MMA.</p>