Effect of locally delivered IGF-1 on nerve regeneration during aging: an experimental study in rats.
Age is an important predictor of neuromuscular recovery after peripheral nerve injury. Insulin-like growth factor 1 (IGF-1) is a potent neurotrophic factor that is known to decline with increasing age. The purpose of this study was to determine if locally delivered IGF-1 would improve nerve regeneration and neuromuscular recovery in aged animals. Young and aged rats underwent nerve transection and repair with either saline or IGF-1 continuously delivered to the site of the nerve repair. After 3 months, nerve regeneration and neuromuscular junction morphology were assessed. In both young and aged animals, IGF-1 significantly improved axon number, diameter, and density. IGF-1 also significantly increased myelination and Schwann cell activity and preserved the morphology of the postsynaptic neuromuscular junction (NMJ). These results show that aged regenerating nerve is sensitive to IGF-1 treatment.
Apel
Peter J
PJ
Department of Orthopaedic Surgery, Wake Forest University Baptist Medical Center, Medical Center Boulevard, Winston-Salem, North Carolina 27157, USA.
Ma
Jianjun
J
Callahan
Michael
M
Northam
Casey N
CN
Alton
Timothy B
TB
Sonntag
William E
WE
Li
Zhongyu
Z
D000367:Age Factors; D000375:Aging / Q000187:drug effects* / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D001369:Axons / Q000187:drug effects / Q000502:physiology; D019922:GAP-43 Protein / Q000235:genetics / Q000378:metabolism; D007334:Insulin-Like Growth Factor I / Q000008:administration & dosage*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D009413:Nerve Fibers, Myelinated / Q000187:drug effects / Q000502:physiology; D009416:Nerve Regeneration / Q000187:drug effects* / Q000502:physiology; D009469:Neuromuscular Junction / Q000187:drug effects / Q000502:physiology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012583:Schwann Cells / Q000187:drug effects / Q000502:physiology; D013979:Tibial Nerve / Q000187:drug effects* / Q000293:injuries*
D019922:GAP-43 Protein; D012333:RNA, Messenger; D007334:Insulin-Like Growth Factor I