title: Bowman-Birk inhibitor concentrate prevents atrophy, weakness, and oxidative stress in soleus muscle of hindlimb-unloaded mice.
abstract: Antigravity muscles atrophy and weaken during prolonged mechanical unloading caused by bed rest or spaceflight. Unloading also induces oxidative stress in muscle, a putative cause of weakness. We tested the hypothesis that dietary supplementation with Bowman-Birk inhibitor concentrate (BBIC), a soy protein extract, would oppose these changes. Adult mice were fed a diet supplemented with 1% BBIC during hindlimb unloading for up to 12 days. Soleus muscles of mice fed the BBIC-supplemented diet weighed less, developed less force per cross-sectional area, and developed less total force after unloading than controls. BBIC supplementation was protective, blunting decrements in soleus muscle weight and force. Cytosolic oxidant activity was assessed using 2',7'-dichlorofluorescin diacetate. Oxidant activity increased in unloaded muscle, peaking at 3 days and remaining elevated through 12 days of unloading. Increases in oxidant activity correlated directly with loss of muscle mass and were abolished by BBIC supplementation. In vitro assays established that BBIC directly buffers reactive oxygen species and also inhibits serine protease activity. We conclude that dietary supplementation with BBIC protects skeletal muscle during prolonged unloading, promoting redox homeostasis in muscle fibers and blunting atrophy-induced weakness.
authors.affiliation: Dept. of Physiology, University of Kentucky, Lexington, KY 40536-0298, USA.
authors.forename: Sandrine
authors.initials: S
authors.lastname: Arbogast
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Smith
authors.forename: Yves
authors.initials: Y
authors.lastname: Matuszczak
authors.forename: Brian J
authors.initials: BJ
authors.lastname: Hardin
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Moylan
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Smith
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Ware
authors.forename: Ann R
authors.initials: AR
authors.lastname: Kennedy
authors.forename: Michael B
authors.initials: MB
authors.lastname: Reid
mesh_terms: D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001522:Behavior, Animal; D001835:Body Weight; D003600:Cytosol / Q000378:metabolism; D019417:Hindlimb Suspension; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009119:Muscle Contraction; D018763:Muscle Fatigue; D018908:Muscle Weakness / Q000517:prevention & control*; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism; D009133:Muscular Atrophy / Q000517:prevention & control*; D018384:Oxidative Stress / Q000187:drug effects*; D011480:Protease Inhibitors / Q000494:pharmacology; D013997:Time Factors; D014358:Trypsin Inhibitor, Bowman-Birk Soybean / Q000494:pharmacology / Q000627:therapeutic use*; D014361:Trypsin Inhibitors / Q000494:pharmacology / Q000627:therapeutic use*
chemical_list: D000975:Antioxidants; D011480:Protease Inhibitors; D014358:Trypsin Inhibitor, Bowman-Birk Soybean; D014361:Trypsin Inhibitors