| Objective:SD rats were used to build cartilage defects model,and then injected normal saline,BMSCs and BMSC-MVs respectively.Both repair-associated protein expression and repair effects in cartilage defect sites were evaluated to investigate the effect of BMSC-MVs on repair of knee cartilage defects.Methods:1.The whole bone marrow adherence method was used to isolate,culture and identify BMSCs of SD rats;Microvesicles(MVs)isolated from the cell supernatant of BMSCs by ultracentrifugation,nd morphological observation was performed by electron microscope;2.SD rats with knee cartilage defects were randomly assigned to six groups(6 SD rats in each group),including normal saline group,sham-operated group,BMSCs group,high-dose BMSC-MVs group,medium-dose BMSC-MVs group and low-dose BMSC-MVs group.Cavity injection of double knee joint was conducted once a week and continued for 4 to 8 weeks.3 rats were executed and sampled at4 and 8weeks respectively.3.Repair of of knee cartilage defects were observed carefully.And then repair effect was evaluated by the tissue stain with HE,glycogen and toluidine blue.Both immunohistochemical analysis and RT-PCR was adopted to determine the content of type(II)collagen,type(?)collagen and MMP-13 in repair sites.Wakitani histologic scores were also used in the present study.4.Statistical analysis.Data were analyzed by SPSS13.0 and all measurement data were expressed as mean ± standard deviation.The ANOVA,chi-square test and t test was performed at the.0.05 significance level.Results:1.General observation showed that both MSCs group and low-dose BMSC-MVs group appeared to be more complete,glistening and flattened,and indistinguishable with the surrounding cartilage compared to other experiment groups.2.Immunohistochemicalanalysis showed that Type(II)collagen was expressed in low-dose BMSC-MVs treatment.Glycosaminoglycans(GAGs)in low-dose BMSC-MVs were lower than sham-operated group,but higher than normal saline group;both type(?)collagen and MMP-13 expressions were downregulated compared to BMSCs group and normal saline group.3.At 6 and 10 weeks after operation,low-dose BMSC-MVs group showed a significantly reduction in improved wakitani score(P< 0.05),however no significant difference in this value was observed compared to BMSC group(P> 0.05).Compared with the repair status at 6 weeks of post-operation,a further 4 weeks repairingexhibited a lower Wakitani score in normalsaline group,BMSCs group,low-dose BMSC-MVs group(P< 0.05).4.There was no significant difference in COL-II mRNA expression level between low-dose BMSC-MVs group and BMSCs group at both 6 and 10 weeks of post-operation(P> 0.05).5.Low-dose BMSC-MVs group showed a better performance in improved wakitani score?immunohistochemistry and RT-PCR than high-dose BMSC-MVs group?middledose BMSC-MVs group at both 6 and 10 weeks of post-operation(P< 0.05).Conclusion:Bone Mesenchymal Stem Cell-derived Microcvesiclescan enhancethe cartilage repair in Defect SD Rats,and that is,Bone Mesenchymal Stem Cell can promote the repair of cartilage defects through paracrine way. |
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