Evidence indicating trophic importance of IGF-I in regenerating peripheral nerves.
The mechanisms influencing regeneration of peripheral nerves are incompletely known, but growth factors are supposed to play a key role. In the present study, we demonstrate, with the aid of immunohistochemical methods, that somatomedin C (Sm-C/insulin-like growth factor I/IGF-I) rapidly increased from low to high concentrations, reaching peak values in 2 weeks, in regenerating sciatic nerves of adult rats. In addition, IGF-I was demonstrated extracellularly, never observed in the control nerves. Reactive Schwann cells appeared to be the major source for IGF-synthesis. Higher concentrations were seen in tubulated nerves as compared to sutured ones. It is proposed that IGF-I exerts important growth supporting effects on regenerating peripheral nerves.
D000818:Animals; D005260:Female; D005455:Fluorescent Antibody Technique; D007334:Insulin-Like Growth Factor I / Q000096:biosynthesis*; D009416:Nerve Regeneration; D010525:Peripheral Nerves / Q000502:physiology*; D051381:Rats; D011919:Rats, Inbred Strains; D012583:Schwann Cells / Q000378:metabolism*; D012584:Sciatic Nerve / Q000166:cytology / Q000378:metabolism / Q000502:physiology; D013002:Somatomedins / Q000096:biosynthesis*; D013997:Time Factors
D013002:Somatomedins; D007334:Insulin-Like Growth Factor I