人羊水来源干细胞参与小鼠损伤肌肉修复的实验研究

INVOLVEMENT OF HUMAN AMNIOTIC FLUID COLONY DERIVED STEM CELLS IN REGENERATION OF MOUSE INJURED MUSCLE

目的研究人羊水来源干细胞(human amniotic fluid colony derived stem cells,hAFCSCs)是否参与小鼠肌肉损伤修复过程,探讨应用hAFCSCs治疗肌肉损伤的方法及可行性。方法 B超引导下穿刺抽取人孕中期羊水,体外分离、培养得到hAFCSCs,取第6～8代细胞备用,同时提取总RNA行RT-PCR鉴定干细胞相关基因。取16只6～8周龄Nod/Scid小鼠,体重20～24 g,利用心肌毒素联合X线照射建立双侧胫骨前肌肌肉损伤模型,右侧胫骨前肌内注射hAFCSCs(3.3×107个/mL)30μL作为实验组,左侧胫骨前肌同法注射等量完全培养液(含15%FBS、18%Chang B、2%Chang C、1%青链霉素、1%L-谷氨酰胺的α-MEM培养基)作为对照组。细胞移植术后2、4周各处死小鼠8只,取材行肝细胞生长因子受体(c-Met)、成肌调节因子(Myf-5)、层粘连蛋白(Laminin)、结蛋白(Desmin)与人特异性细胞核有丝分裂器(NuMa)组织免疫双重荧光染色观察。结果原代hAFCSCs培养5～7 d后可见细胞克隆形成;8～10 d后可挑取细胞形态均一的克隆进行稳定传代,6～8代后可获得足量的干细胞。RT-PCR检测示所获得hAFCSCs体外扩增培养至第6代仍表达干细胞相关基因。细胞移植术后2周免疫双重荧光染色示,实验组胫骨前肌内检测到NuMa表达,未检测到hAFCSCs表达肌源性细胞相关表型;术后4周,实验组胫骨前肌内检测到NuMa表达,部分细胞同时表达NuMa和c-Met、Myf-5,部分肌纤维同时表达NuMa和Desmin、Laminin。术后2、4周,对照组胫骨前肌均未检测到NuMa表达。结论 hAFCSCs体外培养后移植到小鼠肌肉损伤部位,可参与损伤肌肉的修复过程。

Objective To study whether human amniotic fluid colony derived stem cells （hAFCSCs） are involved in regeneration of injured muscles in mice and to investigate the method and feasibility of hAFCSCs-based cytotherapy in the treatment ofiniured muscles. Methods Human second-trimester amniotic fluid was collected through ultrasound-guided amniocentesis, hAFCSCs were isolated from second-trimester amniotic fluid and cultured, and the cells at 6th-8th passages were spared. The mRNA was extracted to identify the stem cell related genes by RT-PCR. The muscular injury model of bilateral tibial is anterior muscle was established by cardiotoxin and X-ray irradiation in 16 Nod/Scid mice （aged 6-8 weeks, and weighing 20-24 g）. The hAFCSCs （3.3 x 10^7/mL, 30 μL） were injected into the right injured tibialis anterior muscles as the experimental group, while the same volume of complete medium （α-MEM containing 15%FBS, 18%Chang B, 2%Chang C, 1% penicillin- streptomycin, and 1% L-glutamine） was injected into the left injured tibialis anterior muscles as the control group. At 2 and 4 weeks after cell transplantation, the immunofluorescence staining of tibialis anterior muscles was performed to detect hepatocyte growth factor receptor （c-Met）, myogenic regulatory factor （Myf-5）, Laminin, Desmin, and human specific nuclear mitotic apparatus protein （NuMa）. Results The clone formation was observed at 5-7 days of primary hAFCSCs culture; after 8-10 days, the clones with homogeneous morphology were selected for subculture. Adequate stem cells were available after 6th-8th subculture. RT-PCR analysis showed that hAFCSCs expressed mRNA of the stem cell related genes. The immunofiuorescence double-staining showed that NuMa expressed in tibialis anterior muscles of the experimental group and no myogenic phenotype expressed at 2 weeks after cell transplantation, and that single cell co-expressed NuMa and c-Met or Myf-5 at 4 weeks after cell transplantation. In some myofibers, NuMa and Laminin or Desmin were also co-expressed. No NuMa positive hAFCSCs were detected in the control group at 2 and 4 weeks after cell transplantation. Conclusion hAFCSCs can participate in the regeneration of injured mouse muscle.