title: Growth factor may decrease muscle atrophy secondary to denervation.
abstract: Despite modern microsurgical techniques, functional outcomes following brachial-plexus reconstruction and peripheral-nerve repair are usually unsatisfactory, because irreversible muscle atrophy develops before reinnervation occurs. Insulin growth factor-1 (IGF-1) has been shown to improve muscle regeneration after injury, and may have a role in muscle preservation following denervation. This study evaluated the histologic, immunohistochemical, and electrophysiologic differences between normal and denervated muscle over an 8-week time period, and also evaluated the effects of injecting IGF-1 into denervated muscle. Denervated mice gastrocnemius muscles demonstrated a decrease in muscle diameter, a decrease in muscle weight, early nuclear proliferation, and a decrease in fast twitch and maximum tetanic strength, compared to normal gastrocnemius muscle up to 8 weeks following denervation. Four weeks after denervated muscle was injected with IGF-1 at time zero, however, relative preservation of muscle diameter and weight, and maintenance of electrophysiologic contractile properties were observed. These preliminary data suggest that IGF-1 may prevent muscle atrophy secondary to denervation.
authors.affiliation: Department of Orthopaedic Surgery, University of Pittsburgh Medical Center, PA 15213, USA.
authors.forename: C S
authors.initials: CS
authors.lastname: Day
authors.forename: F
authors.initials: F
authors.lastname: Riano
authors.forename: M M
authors.initials: MM
authors.lastname: Tomaino
authors.forename: B
authors.initials: B
authors.lastname: Buranatanitkit
authors.forename: G
authors.initials: G
authors.lastname: Somogyi
authors.forename: D
authors.initials: D
authors.lastname: Sotereanos
authors.forename: J
authors.initials: J
authors.lastname: Huard
mesh_terms: D000818:Animals; D003714:Denervation / Q000009:adverse effects*; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D007334:Insulin-Like Growth Factor I / Q000627:therapeutic use*; D051379:Mice; D023421:Models, Animal; D009119:Muscle Contraction / Q000502:physiology; D018482:Muscle, Skeletal / Q000294:innervation / Q000502:physiology; D009133:Muscular Atrophy / Q000209:etiology* / Q000517:prevention & control*
chemical_list: D007334:Insulin-Like Growth Factor I