Edwall D, Schalling M, Jennische E, Norstedt G
Karolinska Institute, Huddinge University Hospital, Sweden.
Endocrinology. 1989 Feb;124(2):820-5. doi: 10.1210/endo-124-2-820.
Expression of insulin-like growth factor I (IGF-I) was studied in regenerating skeletal muscle. Irreversible damage to muscle cells was induced in the extensor digitorum longus muscle of adult rats by ischemia, preceded by glycogen depletion. IGF-I mRNA levels during the regeneration process were studied for periods up to 10 days after injury using a solution hybridization assay. Increased IGF-I mRNA levels could be demonstrated within 24 h after injury; maximum levels were achieved in 3 days and decreased to approximately normal levels by 10 days. Changes in IGF-I mRNA levels could not be seen in undamaged contralateral extensor digitorum longus muscles during the experimental period. An increase in IGF-I mRNA was also evident in injured muscles of hypophysectomized animals. In situ hybridization at the time of maximum induction showed the presence of IGF-I mRNA in proliferating myoblasts and in satellite cells. IGF-I, thus, may act as a locally produced non-GH dependent trophic factor during regeneration of skeletal muscle after injury.
在再生骨骼肌中研究了胰岛素样生长因子I（IGF-I）的表达。通过缺血诱导成年大鼠趾长伸肌的肌肉细胞发生不可逆损伤，损伤前先进行糖原耗竭。使用溶液杂交分析法研究损伤后长达10天的再生过程中IGF-I mRNA水平。损伤后24小时内可证明IGF-I mRNA水平升高；3天达到最高水平，到10天时降至大致正常水平。在实验期间，未损伤的对侧趾长伸肌中未见IGF-I mRNA水平变化。垂体切除动物的损伤肌肉中IGF-I mRNA也明显增加。在最大诱导时的原位杂交显示，增殖的成肌细胞和卫星细胞中存在IGF-I mRNA。因此，IGF-I可能在损伤后骨骼肌再生过程中作为局部产生的非生长激素依赖性营养因子发挥作用。
