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Superoxide balance in aging skeletal muscle
Author(s) -
Furlong Meghan J,
Schilling Samantha R,
Hruskocy Heather N,
Limberg Jacqueline K,
Eldridge Marlowe W,
Schrage William G
Publication year - 2008
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.22.1_supplement.1153.4
Subject(s) - skeletal muscle , catalase , nitrotyrosine , oxidative stress , medicine , endocrinology , xanthine oxidase , superoxide dismutase , reactive oxygen species , antioxidant , muscle biopsy , chemistry , biochemistry , nitric oxide , biopsy , enzyme , nitric oxide synthase
The goal of this study was to determine the age‐induced changes in antioxidant and pro‐oxidant status in skeletal muscle. Contracting skeletal muscle is ripe for production of reactive oxygen species, which may contribute to impaired muscle blood flow in older adults by overwhelming NO signaling in arteries. We hypothesized that muscle from older humans would exhibit reduced levels of antioxidant proteins and increased levels of pro‐oxidant proteins. A muscle biopsy was taken from the vastus lateralis muscle in young (18–40 yrs) and older (65–77 yrs) subjects. Muscle fibers were homogenized, adjusted for equal concentrations, and we assessed protein expression via Western blot and ECL. Proteins of interest were superoxide dismutase (SOD‐1, SOD‐2), catalase, and xanthine oxidase (XO). Probing for nitrotyrosine served as a marker for protein oxidative stress. Preliminary results (young n=3, older n = 5) showed that catalase expression was higher in young adults (P=0.04) while SOD‐1 levels were approximately equal. SOD‐2 levels were greater in older adults (P=0.01) as were nitrotyrosine levels. XO levels tended to be higher in the older adult group (P=0.07). These data suggest that aging skeletal muscle shows increased oxidative stress in parallel with lower catalase and higher XO and nitrotyrosine levels. This may ultimately lead to a decrease in NO bioavailability in aging human skeletal muscle during exercise. Funded by the Wisconsin Alumni Research Foundation (WARF).