Jennische E, Skottner A, Hansson H A
Acta Physiol Scand. 1987 Jan;129(1):9-15. doi: 10.1111/j.1748-1716.1987.tb08034.x.
The expression of insulin-like growth factor I (IGF-I, somatomedin C) was studied in regenerating skeletal muscle. Irreversible damage to skeletal muscle cells was induced in the extensor digitorum longus muscle (EDL) of adult rats by ischaemia, preceded by glycogen depletion, and the regeneration process was studied for periods up to 14 days after injury. The IGF-I was demonstrated by indirect immunofluorescence. Immunoreactivity against ribonucleotide reductase (RR) was used as a marker for DNA synthesis, that is, cell proliferation. Increased IGF-I immunoreactivity could be demonstrated within 24 h after injury in satellite cells, intramuscular nerves and in blood vessels. The IGF-I immunoreactivity remained virtually unchanged in the contralateral, undamaged EDL. An increasing number of satellite cells, expressing high IGF-I immunoreactivity, could be demonstrated in the injured EDL, and within 72 h myoblasts, expressing high IGF-I and RR immunoreactivity, were formed. Small immature muscle cells, displaying high IGF-I immunoreactivity, were observed 4 days after injury. Increased IGF-I immunoreactivity was still obvious in the regenerated muscle cells 14 days after injury while RR immunoreactivity was seen only in scattered satellite cells. It is concluded that IGF-I may act as a trophic factor during regeneration of skeletal muscle after injury.
研究了胰岛素样生长因子I（IGF-I，生长调节素C）在再生骨骼肌中的表达。通过缺血诱导成年大鼠趾长伸肌（EDL）的骨骼肌细胞发生不可逆损伤，损伤前糖原耗竭，并在损伤后长达14天的时间内研究再生过程。通过间接免疫荧光法检测IGF-I。将针对核糖核苷酸还原酶（RR）的免疫反应性用作DNA合成（即细胞增殖）的标志物。损伤后24小时内，卫星细胞、肌内神经和血管中可检测到IGF-I免疫反应性增加。对侧未受损的EDL中，IGF-I免疫反应性几乎保持不变。在受损的EDL中，可检测到越来越多表达高IGF-I免疫反应性的卫星细胞，并且在72小时内形成了表达高IGF-I和RR免疫反应性的成肌细胞。损伤后4天观察到显示高IGF-I免疫反应性的小的未成熟肌细胞。损伤后14天，再生肌细胞中IGF-I免疫反应性仍然明显增加，而RR免疫反应性仅在散在的卫星细胞中可见。结论是，IGF-I可能在损伤后骨骼肌再生过程中作为一种营养因子发挥作用。
