成体脂肪来源的Flk-1^+间充质干细胞用于杜氏肌营养不良症治疗的可行性研究

Mice Adipose Derived Flk-1^+ Mesenchymal Stem Cells Can Ameliorate Duchenne's Musclular Dystrophy in Mdx Mice for Their Multilineage Potential

为了探讨成体脂肪来源的间充质干细胞(adipose derived mesenchymal stemcell,AD-MSC)移植治疗杜氏肌营养不良症(Duchenne muscular dystrophy,DMD)的可行性,从成年GFP小鼠脂肪组织中分离得到间充质干细胞(mesen-chymal stem cell,MSC),用流式细胞术分析其细胞表型和细胞周期;在体外分别以成肌和成内皮诱导体系诱导AD-MSC的定向分化,通过免疫荧光染色和RT-PCR进行鉴定;经尾静脉移植AD-MSC到CTX肌肉损伤模型小鼠和mdx小鼠(DMD动物模型)体内,通过RT-PCR和免疫荧光染色检测供体细胞的分布和分化情况,并进行统计分析。结果表明:从GFP小鼠脂肪组织中分离得到的Flk-1+MSC可以在体外分化为肌肉细胞和血管内皮细胞;细胞移植后,可在损伤肌肉部位检测到GFP阳性的肌纤维、血管内皮细胞和肌肉干细胞;mdx小鼠移植后肌膜上抗肌萎缩蛋白(dystro-phin)的表达部分恢复,骨骼肌中心核肌纤维比例也大大降低。结论:AD-MSC是一种较为理想的供移植治疗DMD的干细胞,它不仅可以定向归巢到损伤的肌肉组织中,参与肌纤维重建,而且能改善组织供血,缓解DMD病征,同时部分供体细胞以干细胞形式存在,可以代替原来肌肉干细胞的功能,不断修复损伤的肌肉组织。

Duchenne muscular dystrophy （DMD） is a common X-linked disease characterized by widespread muscle damage that invariably leads to paralysis and death. There is currently no therapy for this disease. This study was purposed to investigate the feasibility to use adult adipose-derived mesenchymal stem cells （AD-MSCs） in the therapy of DMD. The Flk-1^＋ MSCs were isolated from adipose tissue of adult GFP mice; the phenotype and cell cycle of MSCs were analyzed by flow cytometry; the AD-MSCs were directionally differentiated by myoblast and endotheliablast induction system /n vitro and were identified by immumofluorecence staining and RT-PCR; the AD-MSCs were transplanted into CTX-injured mice model or mdx mice （DMD animal model） through tail vein; the distribution and differentiation of AD-MSCs were detected by immunofhorescence staining and RT-PCR respectively, and statistic analysis was performed. The results showed that the Flk-1^＋ AD-MSCs could be induced to differentiate into myoblasts and endothelial cells in vitro, After transplanted into CTX-injured mice model or mdx mice, GFP-positive cells could be detected in damaged muscle, and these donor-derived ceils were also positive for MHC, vWF, or Pax7. Flk-1^＋ AD- MSC transplantation also partly reconstituted the expression of dystrophin, and reduced the percentage of centronucleated myofibers in mdx mice. It is concluded that Flk-1^＋ AD-MSCs represent a possible tool for future cell therapy applications in DMD disease, as they can be delivered through the circulation for their potential of muscle homing. And Flk-1^＋ AD-MSCs also show the ability to contribute to muscle repair, improvement of blood supply and long term reconstitution of dystrophy muscle.