title: Effects of eccentric treadmill exercise on inflammatory gene expression in human skeletal muscle.
abstract: The present study examined the skeletal muscle expression of several genes related to the inflammatory process before and after a bout of downhill running. Twenty-nine males between the ages of 18 and 35 years performed a 45-min downhill (-17.5%) treadmill protocol at 60% of maximal oxygen consumption. Venous bloods samples and muscle biopsy samples from the vastus lateralis were donated prior to and at 3-h and 24-h postexercise, along with ratings of perceived muscle soreness. Serum creatine kinase (CK) was determined, as was skeletal muscle gene expression of interleukin (IL)-6, IL-8, IL-12 (p35), tumor necrosis factor-alpha (TNF-alpha), IL-1beta, cyclooxygenase 2 (COX2), and nuclear factor kappa B (NFkB) (p105/p50). Gene expression was analyzed using RT-PCR and compared with a standard housekeeping gene (beta-actin). Data were analyzed for statistical differences using multivariate analysis of variance with univariate follow-up. In addition, Pearson correlations were conducted to determine if any significant relationship exists between any of these transcripts and both CK and muscle soreness. Significant (p < 0.05) up-regulations in IL-6, IL-8, and COX2 mRNA expression were observed compared with baseline, whereas no significant changes for IL-12, IL-1beta, TNF-alpha, or NFkB were noted. Significant increases in IL-6 mRNA were observed at 3 h (p < 0.001) and 24 h (p = 0.043), whereas significant increases in IL-8 (p = 0.001) and COX2 (p = 0.046) mRNA were observed at 3-h postexercise. In addition, muscle soreness was significantly correlated with IL-8 at 24 h (r = -0.370; p = 0.048), whereas CK was significantly related to NFkB at baseline (r = -0.460; p = 0.012). These data indicate that increases in the mRNA expression of IL-6, IL-8, and COX2 occur in the vastus lateralis as a result of damaging eccentric exercise in young, recreationally trained males. Further, it appears that IL-8 transcription may play some role in inhibiting postexercise muscle soreness, possibly through regulation of angiogenesis.
authors.affiliation: Exercise and Biochemical Nutrition Laboratory, Baylor University, Waco, TX 76798, USA.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Buford
authors.forename: Matthew B
authors.initials: MB
authors.lastname: Cooke
authors.forename: Brian D
authors.initials: BD
authors.lastname: Shelmadine
authors.forename: Geoffrey M
authors.initials: GM
authors.lastname: Hudson
authors.forename: Liz
authors.initials: L
authors.lastname: Redd
authors.forename: Darryn S
authors.initials: DS
authors.lastname: Willoughby
mesh_terms: D000293:Adolescent; D000328:Adult; D052283:Creatine Kinase, MM Form / Q000097:blood; D051546:Cyclooxygenase 2 / Q000235:genetics; D015444:Exercise; D005786:Gene Expression Regulation; D006801:Humans; D007249:Inflammation / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D018836:Inflammation Mediators / Q000378:metabolism*; D007378:Interleukins / Q000235:genetics; D008297:Male; D009119:Muscle Contraction / Q000235:genetics*; D018482:Muscle, Skeletal / Q000378:metabolism* / Q000473:pathology; D016328:NF-kappa B / Q000235:genetics; D012333:RNA, Messenger / Q000378:metabolism*; D012420:Running; D013997:Time Factors; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics; D055815:Young Adult
chemical_list: D018836:Inflammation Mediators; D007378:Interleukins; D016328:NF-kappa B; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D052283:Creatine Kinase, MM Form