title: Supplemental nitric oxide augments satellite cell activity on cultured myofibers from aged mice.
abstract: Skeletal muscle regenerative potential is reduced with aging. We hypothesized that in vitro activation of muscle satellite cells would be compromised, and that nitric oxide (NO) supplementation would improve satellite cell activity in old muscle. Single intact myofibers were isolated from the gastrocnemius muscles of young (2 mo), adult (10 mo), and aged (22 mo) mice. Fibers were centrifuged to stimulate satellite cells and incubated with L-arginine (2mM), the NO donor, diethylenetriamine NONOate (DETA-NO; 10 microM), or control media for 48 h. The number of activated satellite cells after centrifugation was reduced in aged fibers compared to young and adult. L-arginine or DETA-NO treatment increased satellite cell activation in all age groups. However, an age-dependent deficit in satellite cell activity persisted within treatment groups. In separate fibers, exogenous HGF was equally effective in activating satellite cells across age groups, indicating that events downstream of HGF release are intact in aged muscle. These data suggest that l-arginine bioavailability and NO production limit muscle satellite cell activity in response to a submaximal mechanical stimulus, regardless of age. Further, the decline in satellite cell activity in early senescence can be partially abrogated by exogenous L-arginine or an NO donor.
authors.affiliation: Center for Exercise Science, Department of Applied Physiology & Kinesiology, University of Florida, P.O. Box 118206, Gainesville, FL 32611, USA.
authors.forename: Jenna L
authors.initials: JL
authors.lastname: Betters
authors.forename: Vitor A
authors.initials: VA
authors.lastname: Lira
authors.forename: Quinlyn A
authors.initials: QA
authors.lastname: Soltow
authors.forename: Jason A
authors.initials: JA
authors.lastname: Drenning
authors.forename: David S
authors.initials: DS
authors.lastname: Criswell
mesh_terms: D000375:Aging / Q000502:physiology; D000818:Animals; D015153:Blotting, Western; D049109:Cell Proliferation; D002478:Cells, Cultured; D019417:Hindlimb Suspension; D007334:Insulin-Like Growth Factor I / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009412:Nerve Fibers / Q000502:physiology*; D009569:Nitric Oxide / Q000378:metabolism*; D032496:Satellite Cells, Skeletal Muscle / Q000378:metabolism*; D013314:Stress, Mechanical
chemical_list: D009569:Nitric Oxide; D007334:Insulin-Like Growth Factor I