Time course of changes in markers of myogenesis in overloaded rat skeletal muscles
Time course of changes in markers of myogenesis in overloaded rat skeletal muscles
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DOI：
10.1152/jappl.1999.87.5.1705
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发表时间：
1999-11-01
影响因子：
3.3
通讯作者：
Baldwin, KM
中科院分区：
文献类型：
--
作者：
Adams, GR;Haddad, F;Baldwin, KM
在代偿性肌肉肥大的过程中，卫星细胞被认为增殖、分化，然后与现有的肌纤维融合。我们假设，在该过程的早期，指示肌源性过程开始的细胞标记物的表达发生变化。通过单侧切除增效剂使大鼠跖肌超负荷。各组大鼠在6 h至12 d的时间点处死。测量细胞周期蛋白D1、p21、肌细胞生成素、MyoD和胰岛素样生长因子I（IGF-I，mRNA和肽）的肌肉基因表达（mRNA）的变化。细胞周期蛋白D1（细胞周期标志物）增加后24小时的超载和肌肉DNA含量的变化相对应。相比之下，p21和肌细胞生成素，细胞分化的标志物，增加后仅12小时。肌肉IGF-I肽水平也在早期时间点增加。这项研究的结果表明，肌源性过程在非常早的时间点（例如，12 h），IGF-I可能调节这种反应。此外，这些发现表明，在导致细胞增殖的事件开始之前，一些细胞可能在适应过程中很早就分化了。
During the process of compensatory muscle hypertrophy, satellite cells are thought to proliferate, differentiate, and then fuse with existing myofibers. We hypothesized that early in this process changes occur in the expression of cellular markers indicative of the onset of myogenic processes. The plantaris muscles of rats were overloaded via the unilateral ablation of synergists. Groups of rats were killed at time points from 6 h to 12 days. Changes in muscle gene expression (mRNA) of cyclin D1, p21, myogenin, MyoD, and insulin-like growth factor I (IGF-I, mRNA and peptide) were measured. Cyclin D1 (a cell cycle marker) was increased after 24 h of overloading and corresponded with changes in muscle DNA content. In contrast, p21 and myogenin, markers of cellular differentiation, were increased after just 12 h. Muscle IGF-I peptide levels were also increased at early time points. The results of this study indicate that myogenic processes are activated in response to increased loading at very early time points (e.g., 12 h) and that IGF-I may be modulating this response. Furthermore, these findings suggest that some cells may have been differentiating very early in the adaptation process before events leading to cellular proliferation have been initiated.