人骨髓间充质干细胞能部分修补mdx鼠膈肌肌膜

Human bone marrow mesenchymal stem cells can partly restore sarcolemma of diaphragm of mdx mice

目的探讨人骨髓间充质干细胞(hBM-MSC)移植mdx鼠后是否能修补膈肌肌膜。方法用5-溴脱氧尿嘧啶核苷(BrdU)标记hBM-MSC,将1×107个干细胞(0.3mL)经尾静脉注入免疫抑制的mdx鼠(8～10周龄)体内。于移植后2、4、8、12、16、20及24周处死mdx鼠,用免疫组化法检测膈肌的病理变化、BrdU阳性细胞核数及人细胞核(Hu)与人抗肌萎缩蛋白(Dys)的表达,RT-PCR检测人Dys mRNA的表达。结果移植mdx鼠膈肌核中心移位纤维比例较未移植mdx鼠显著减少(P<0.05)。移植后2周膈肌可检测到少量BrdU阳性细胞核,8周后膈肌的BrdU阳性细胞核数逐渐增加。移植后2周膈肌检测到少量人特异性抗核(anti-Hu)抗体阳性细胞核,4周后在膈肌肌膜可见少量人特异性Dys阳性细胞,8周后有Dys mRNA的表达;随着移植时间的延长,anti-Hu抗体阳性细胞核数和Dys阳性细胞比例逐渐增高,Dys mRNA的表达逐渐增强。结论hBM-MSCs可在mdx鼠膈肌分化为肌细胞,能减轻膈肌的病理,部分修补膈肌肌膜。

【Objective】To investigate whether human bone marrow mesenchymal stem cells （hBM-MSCs） restore sarcolemma of diaphragm in mdx mice.【Methods】Twenty-one 8 to 10 week-old immunosuppressed mdx mice were transplanted with 1×107 passage 5 of hBM-MSCs labeled with bromodeoxyuridine （BrdU） by means of injection into the tail vein.The mice were euthanized at 2,4,8,12,16,20 and 24 weeks after transplantation,respectively.The diaphragm muscles of the mice were performed for HE staining,immunofluorescent detection of BrdU and antihuman nuclei mouse monoclonal antibody （anti-Hu）,and analyzed for human dystrophin （Dys） expression by immunohistochemistry and reverse transcript polymerase chain reaction （RT-PCR）.【Results】The proportion of centrally nucleated fibers （CNF） in the diaphragm muscle of the recipient mdx mice was significantly smaller than that of untreated mdx mice.BrdU positive cells were found in part sarcolemma of diaphragm muscle at 2 weeks,increased gradually after 8 weeks of transplantation.Little anti-Hu positive cells were detected in diaphragm muscle 2 weeks after transplantation.Dys positive cell were seldom found at 4 weeks and small Dys mRNA expression detected at 8 weeks after transplant.The proportion of anti-Hu in parallel with Dys positive cells and Dys mRNA in diaphragm muscle of mdx mice increased gradually over time of transplant.【Conclusion】The results suggested that hBM-MSCs can differentiate into skeletal muscle cells in vivo,reduce the pathology in the diaphragm muscle of mdx mice and partly restore sarcolemma of diaphragm in mdx mice.