| Objectives:Spinal cord injury is a serious complication of the disease of spine, often results in severe dysfunctions of motor and sensory under the injury stage.SCI continues to be a devastating injury to themselves and their families, they bear the biggest burden of the disease, such as an enormous financial, psychological and emotional cost to them and to society. With technological advances in cell technology, stem cell-based therapy became a reliable and effective method. An array of MSCs from many sources with new and promising methods are being used to improve the function after SCI. MSCs are self-renewing, multi-potent progenitor cells with the capacity to differentiate into several distinct mesenchymal lineages. Because the low survival and differentiation rate, its experimental study and further application is limited. Micro-RNA widely exists in biological body, regulates the gene expression and individual development. Several trials have investigated the efficacy of micro-RNA in differentiate of stem cells. Today, we research the effects of mi RNA-let-7b-modified bone mesenchymal stem cells transplantation on the repair of nerve in rats with spinal cord injury. Methods:60 SD rats were randomly divided into three groups, each group including 20 rats:control group(n=20), BMSCs group(n=20), and micro-RNA group(n=20). the control group received the physical saline in the injury region,1 week after the SCI model were established, and BMSCs infected with empty virus were injected in the same place in BMSCs group, and the rats of miRNA group were treated with the BMSCs transfect with microRNA-let-7b lentiviral vector. The neurological functions were evaluated, using the Basso-Beattie-Bresnahan(BBB) scale, 1week? 2 weeks? 4 weeks and 8 weeks after manufacturing model. NSE?MAP-1?and VIM of the spinal cord were detected. The expression of mRNA NGF in spinal cord injury area was detected by Rt-PCR method.Using SPSS15.0 software for statistical analysis. Statistical analysis of data was performed using a one-way analysis of variance(ANOVA); data were performed using t test when homogeneity of variance. Using Tamhane's T2 test when heterogeneity of variance. Statistical significance was assumed if P < 0.05. Results:1. All groups of rats have severe hind limbs dysfunction after operation, and compare with the scores of three groups, there was no significant(P>0.05). After the transplantation, BBB score of rats 3 group were rising, the motor function of lower limbs of rats have also improved, the comparison of BBB scores in three groups at all time points : miRNA group is highest, the second is BMSCs group and control group is lowest. The difference was statistically significant(P<0.05).2. HE staining shows: three groups of rat spinal cord tissues are visible organization structure disorder, edema, pathological changes, such as nerve cells of miRNA group and BMSCs group pathology change than those in control group.3. With the experimental progress, 1 week, 2 weeks, 4 weeks, 8 weeks after cell transplantation,NSE?MAP-1?and VIM staining positive cells number are increasing, the largest group is miRNA group, BMSCs group followed, the least is control group, The difference was statistically significant(P<0.05)4. The expression levels of mRNA NGF in spinal cord were from high to low in order to miRNA-let7 b group, MSCs group, sham operation group, and the difference between the two groups was statistically significant(P<0.05). Conclusion:1.Bone mesenchymal stem cells modified with miRNA let-7b transplantation can differentiate into NSE?MAP-1?and VIM in the microenvironment of spinal cord, Bone marrow mesenchymal stem cell can improve the movement of hind limbs of rats with spinal cord injury and the therapy of bone marrow mesenchymal stem cell modified miRNA let- 7 b is better.2. Bone marrow mesenchymal stem cell modified miRNA let- 7 b can reduce the pathological changes of rats after spinal cord injury. |
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