title: Acute phase response in exercise. III. Neutrophil and IL-1 beta accumulation in skeletal muscle.
abstract: Nine untrained men (22-29 yr) performed 45 min of downhill running (16% incline, 70% of maximum heart rate). Needle biopsies of the vastus lateralis were performed before, 45 min after, and 5 days after exercise. Immunohistochemical staining of muscle cross sections revealed a 135% increase in muscle interleukin-1 beta (IL-1 beta) immediately after and a 250% increase (P < 0.03) 5 days after exercise. Using a rating scale (0-3) for the presence of neutrophils, light microscopic examination showed a significant accumulation of neutrophils in muscle biopsies taken 45 min after and 5 days after exercise [before: 0.5 +/- 0.2, 45 min after: 1.5 +/- 0.3 (P < 0.01), and 5 days after: 1.2 +/- 0.2 (P < 0.04)]. In addition, electron microscopic analysis showed an increase in the percentage of damaged Z-bands relative to total Z-bands [before: 4.8 +/- 3.5%, 45 min after: 32.5 +/- 8.6% (P < 0.05), and 5 days after: 14.1 +/- 3.2%]. Neutrophil accumulation was positively correlated to intracellular Z-band damage (rho = 0.66, P < 0.001). Immunohistochemical staining for IL-1 beta was related to neutrophil accumulation in muscle (rho = 0.38, P < 0.06) and to plasma creatine kinase levels (rho = 0.416, P < 0.04). These data indicate that after eccentric exercise ultrastructural damage to skeletal muscle is associated with neutrophil infiltration and muscle IL-1 beta accumulation.
authors.affiliation: United States Department of Agriculture Human Nutrition Research Center on Aging, Tufts University, Boston, Massachusetts 02111.
authors.forename: R A
authors.initials: RA
authors.lastname: Fielding
authors.forename: T J
authors.initials: TJ
authors.lastname: Manfredi
authors.forename: W
authors.initials: W
authors.lastname: Ding
authors.forename: M A
authors.initials: MA
authors.lastname: Fiatarone
authors.forename: W J
authors.initials: WJ
authors.lastname: Evans
authors.forename: J G
authors.initials: JG
authors.lastname: Cannon
mesh_terms: D000210:Acute-Phase Reaction; D000328:Adult; D003402:Creatine Kinase / Q000378:metabolism; D006801:Humans; D007375:Interleukin-1 / Q000378:metabolism*; D008297:Male; D008854:Microscopy, Electron; D009132:Muscles / Q000166:cytology / Q000378:metabolism* / Q000648:ultrastructure; D009504:Neutrophils / Q000166:cytology*; D005082:Physical Exertion
chemical_list: D007375:Interleukin-1; D003402:Creatine Kinase