title: Assessment of exercise-induced alterations in neutrophil function in horses.
abstract: OBJECTIVE
  To evaluate the effects of a standardized exercise test to exhaustion in horses on leukocyte function ex vivo.
  
  
  METHODS
  6 Thoroughbred geldings.
  
  
  METHODS
  Blood samples were obtained from each horse before exercise; at exhaustion (termed failure); and at 2, 6, 24, 48, and 72 hours after exercise to evaluate hematologic changes, rate of leukocyte apoptosis, and leukocyte production of reactive oxygen species (ROS) ex vivo. To assess leukocyte function, leukocyte ROS production in response to stimulation with lipopolysaccharide, peptidoglycan, zymosan, and phorbol myristate acetate was evaluated. Apoptosis was evaluated via assessment of caspase activity in leukocyte lysates.
  
  
  RESULTS
  In response to lipopolysaccharide, production of ROS by leukocytes was significantly increased at 2 hours and remained increased (albeit not significantly) at 6 hours after exercise, compared with the preexercise value. In the absence of any stimulus, leukocyte ROS production was significantly increased at 6 and 24 hours after exercise. In contrast, ROS production in response to phorbol myristate acetate was significantly decreased at 6, 24, and 72 hours after exercise. Leukocyte ROS production induced by zymosan or peptidoglycan was not altered by exercise. Leukocytosis was evident for 24 hours after exercise, and neutrophilia was detected during the first 6 hours. A significant increase in the rate of leukocyte apoptosis was detected at failure and 72 hours after exercise.
  
  
  CONCLUSIONS
  Results indicated that strenuous exercise undertaken by horses causes alterations in innate immune system functions, some of which persist for as long as 72 hours after exercise.
authors.affiliation: Department of Population Health and Large Animal Medicine, College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA.
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Donovan
authors.forename: Christie A
authors.initials: CA
authors.lastname: Jackson
authors.forename: Patrick T
authors.initials: PT
authors.lastname: Colahan
authors.forename: Natalie N
authors.initials: NN
authors.lastname: Norton
authors.forename: Joan L
authors.initials: JL
authors.lastname: Clapper
authors.forename: James N
authors.initials: JN
authors.lastname: Moore
authors.forename: David J
authors.initials: DJ
authors.lastname: Hurley
mesh_terms: D000818:Animals; D017209:Apoptosis / Q000276:immunology; D020169:Caspases / Q000378:metabolism; D006736:Horses / Q000276:immunology* / Q000378:metabolism; D007958:Leukocyte Count / Q000662:veterinary; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D018375:Neutrophil Activation / Q000276:immunology; D009504:Neutrophils / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D010457:Peptidoglycan / Q000494:pharmacology; D010805:Physical Conditioning, Animal / Q000502:physiology*; D017382:Reactive Oxygen Species / Q000276:immunology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D015054:Zymosan / Q000276:immunology / Q000494:pharmacology
chemical_list: D008070:Lipopolysaccharides; D010457:Peptidoglycan; D017382:Reactive Oxygen Species; D015054:Zymosan; D020169:Caspases; D013755:Tetradecanoylphorbol Acetate