Fatiguing exercise reduces DNA binding activity of NF-kappaB in skeletal muscle nuclei.
This study tested the hypothesis that skeletal muscle contraction activates nuclear factor-kappaB (NF-kappaB), a putative regulator of muscle protein breakdown. Muscle biopsies were obtained from the vastus lateralis of healthy humans before, immediately after, and 1 h after fatiguing resistance exercise of the lower limbs. Biopsies were analyzed for nuclear NF-kappaB DNA binding activity by using electrophoretic mobility shift assay. NF-kappaB activity, measured immediately after exercise, was less than preexercise activity; after 1-h recovery, activity returned to preexercise levels. In follow-up studies in adult mice, basal NF-kappaB activity varied among individual muscles. NF-kappaB activity in diaphragm fiber bundles was decreased after a 10-min bout of fatiguing tetanic contractions in vitro. NF-kappaB activity in soleus was increased by 12 days of unloading by hindlimb suspension; this increase was reversed by 10 min of fatiguing exercise. These data provide no support for our original hypothesis. Instead, acute fatiguing exercise appears to decrease NF-kappaB activity in muscle under a variety of conditions.
Durham
William J
WJ
Pulmonary and Critical Care Medicine Section, Baylor College of Medicine, Houston, Texas 77030, USA.
Li
Yi-Ping
YP
Gerken
Eric
E
Farid
Mehran
M
Arbogast
Sandrine
S
Wolfe
Robert R
RR
Reid
Michael B
MB
D000328:Adult; D000818:Animals; D004247:DNA / Q000378:metabolism*; D003964:Diaphragm / Q000378:metabolism; D015444:Exercise / Q000502:physiology*; D005260:Female; D006614:Hindlimb; D019417:Hindlimb Suspension; D006801:Humans; D007866:Leg; D008099:Liver / Q000378:metabolism; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D018763:Muscle Fatigue / Q000502:physiology*; D018482:Muscle, Skeletal / Q000378:metabolism*; D016328:NF-kappa B / Q000378:metabolism*; D013997:Time Factors
D016328:NF-kappa B; D004247:DNA