Düsterhöft S, Pette D
Fakultät für Biologie, Universität Konstanz, Germany.
Differentiation. 1993 May;53(1):25-33. doi: 10.1111/j.1432-0436.1993.tb00642.x.
Satellite cells were isolated at high yields from slow-twitch soleus and fast-twitch tibialis anterior (TA) muscles of adult male Wistar rats. The number of satellite cells isolated from soleus muscle exceeded that from TA muscles by a factor of three. A comparison of satellite cells grown on gelatin- or Matrigel-coated dishes revealed that Matrigel greatly enhances the maturation of the satellite-cell-derived myotubes. As judged from immunohistochemistry, myosin heavy chain electrophoresis and immunoblot analyses, only cells grown on Matrigel, but not on gelatin, expressed adult myosin isoforms. Slow myosin expression was only detected in Matrigel cultures. Soleus cultures contained, in addition to the majority of myotubes expressing fast myosin, a small fraction (maximally 10%) of myotubes coexpressing fast and slow myosins. The number of fast/slow myosin-containing myotubes was negligible in TA cultures. The expression of slow myosin increased with age. Slow myosin was nonuniformly distributed along the length of specific myotubes and accumulated around some myonuclei. These results point to the existence of myotubes with a heterogeneous population of myonuclei, probably resulting from fusion of differently preprogrammed satellite cells. We suggest that the patch-like expression of slow myosin results from local accumulation of myonuclei of slow-type satellite cells.
从成年雄性Wistar大鼠的慢肌比目鱼肌和快肌胫骨前肌（TA）中以高产率分离出卫星细胞。从比目鱼肌分离出的卫星细胞数量比从TA肌分离出的卫星细胞数量多两倍。对在明胶或基质胶包被的培养皿上生长的卫星细胞进行比较发现，基质胶极大地促进了卫星细胞来源的肌管的成熟。从免疫组织化学、肌球蛋白重链电泳和免疫印迹分析判断，只有在基质胶上生长的细胞，而不是在明胶上生长的细胞，表达成年肌球蛋白异构体。慢肌球蛋白表达仅在基质胶培养物中检测到。比目鱼肌培养物中，除了大多数表达快肌球蛋白的肌管外，还有一小部分（最多10%）肌管同时表达快肌球蛋白和慢肌球蛋白。在TA培养物中，含快/慢肌球蛋白的肌管数量可以忽略不计。慢肌球蛋白的表达随年龄增加。慢肌球蛋白沿特定肌管长度分布不均匀，并在一些肌核周围积累。这些结果表明存在具有异质肌核群体的肌管，这可能是由于不同预编程的卫星细胞融合所致。我们认为慢肌球蛋白的斑块状表达是由于慢型卫星细胞的肌核局部积累所致。
