| Objective To investigate the mechanism and characteristics of methylprednisolone(MP)in the treatment of spinal cord injury(SCI)in rats by bone marrow mesenchymal stem cells(BMSCs)using the pharmacological characteristics of methylprednisolone and the biological characteristics of bone marrow mesenchymal stem cells.Method Femurs and tibia bone marrow were isolated from 4-week-old male SD rats and cultured intothird generation with full adherence.The morphological changes were observed and the third generation BMSCs was identifiedby flow cytometry,collected and labeled with 5-bromo-2-deoxyuridine(Brd U)solution.Forty male Sprague-Dawley(SD)rats were used to establish the models of spinal cord injury according to the modified Allen's contusion method and randomly divided into four groups(each group,n=10).Group A was blank control whose spinal treatment nothing MP treatment or BMSCs were implanted or BMSCs plus MP in groups B,C,and D,respectively.MP was administrated by application of intravenous of methylprednisoloneimmediatelyafter SCI,BMSCs were transplanted into the injured sites of spinal cord after two hours of SCI.At 1?3?7?10 and 14 days after SCI,when functional outcome measurements have evaluated by the BBB score,at 14 day after treatment,the spine cord tissues were harvested for the TNF-?,IL-1? immunohistochemistry,and TUNEL staining method was used to detect cell apoptosis rate.The positive rate of BMSC in group C and group D was calculated.Analyze data with software SPSS20.0.Results There was no significant difference in the activity of lower limbs between the four groups(P>0.05).Compared with the group A,the scores of group B and group D were higher than those of the group A(P <0.05),Compared with the group A,group B and group D score in the 3 days after treatment were higher than the same period and the BMSCs group increased after 5 days(P <0.05).At 3,7,10 and 14 days after operation,B,C and D were significantly higher than those in group A,the difference was statistically significant(P <0.05),D group was significantly higher than B,C group,the difference was statistically significant(P <0.05).At 14 days,immunohistochemistry staining presented that the TNF-? and IL-1? positive cells in group D were obviously lower than groups Band C,and group A was higher than group Band group C.TUNEL staining showed the apoptotic rate of spinal cord cells of group D was least in four groups,compared with the group A,the apoptotic rate significantly decreased in group B and group C;comparedwith the group D,the apoptotic rate was significantly decreased in the group B and C.Brd U staining revealed BMSCssurvival rate of group D were significantly higher than group C,and there are statistic difference between two groups(P <0.05).Conclusion 1?Both methylprednisolone and BMSCs could improve the neurological recovery of spinal cord injury rats,and the combined treatment was better.2 ? Both methylprednisolone and BMSCs could decrease the expression of local TNF-? and IL-1? and decrease the apoptosis of the injured site.The effect of methylprednisolone was stronger than that of BMSCs,and the synergistic effect was enhanced.3?The effective survival rate of transplanted BMSCs was improved by methylprednisolone. |
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