title: Induction of lymphocyte death by short- and long-duration triathlon competitions.
abstract: OBJECTIVE
  The effect of triathlon competitions on death of lymphocytes from elite athletes was investigated.
  
  
  METHODS
  Blood was collected from sedentary volunteers and triathletes at rest and after a short-duration triathlon (SDT) and after a long-duration triathlon (LDT-half Ironman) competitions.
  
  
  RESULTS
  The athletes had lowered lymphocyte proliferation capacity compared with sedentary volunteers either at rest or after the competitions. There was no difference in the parameters associated with lymphocyte death when sedentary volunteers were compared with triathletes at rest. Lymphocytes from triathletes after SDT competition showed an increase in DNA fragmentation, phosphatidylserine externalization, and mitochondrial transmembrane depolarization and did not alter membrane integrity when compared with cells from athletes at rest. In contrast, the LDT competition raised the proportion of lymphocytes with loss of membrane integrity when compared with cells from athletes at rest and did not change the apoptotic parameters. The LDT competition induced an increase of reactive oxygen species (ROS) production by lymphocytes compared with triathletes at rest. The SDT competition did not alter ROS production by lymphocytes when compared with cells from triathletes at rest. ROS production by lymphocytes after LDT competition was 60% higher than in SDT.
  
  
  CONCLUSIONS
  Evidence is presented herein that an LDT competition caused lymphocyte death by necrosis, whereas an SDT induced lymphocyte apoptosis. The mechanism for lymphocyte death induced by the triathlon competitions may involve an increase in ROS production at different extents.
authors.affiliation: Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, Brazil.
authors.forename: Adriana Cristina
authors.initials: AC
authors.lastname: Levada-Pires
authors.forename: Maria Fernanda
authors.initials: MF
authors.lastname: Cury-Boaventura
authors.forename: Renata
authors.initials: R
authors.lastname: Gorjão
authors.forename: Sandro Massao
authors.initials: SM
authors.lastname: Hirabara
authors.forename: Enrico Fuini
authors.initials: EF
authors.lastname: Puggina
authors.forename: Idico Luiz
authors.initials: IL
authors.lastname: Pellegrinotti
authors.forename: Luiz Antonio
authors.initials: LA
authors.lastname: Domingues Filho
authors.forename: Rui
authors.initials: R
authors.lastname: Curi
authors.forename: Tania Cristina
authors.initials: TC
authors.lastname: Pithon-Curi
mesh_terms: D000328:Adult; D017209:Apoptosis / Q000502:physiology; D001642:Bicycling / Q000502:physiology*; D002462:Cell Membrane / Q000473:pathology; D049109:Cell Proliferation; D053938:DNA Fragmentation; D006801:Humans; D008214:Lymphocytes / Q000378:metabolism / Q000473:pathology* / Q000502:physiology*; D008297:Male; D053078:Membrane Potential, Mitochondrial / Q000502:physiology; D009336:Necrosis / Q000473:pathology; D017382:Reactive Oxygen Species / Q000378:metabolism; D012420:Running / Q000502:physiology*; D013550:Swimming / Q000502:physiology*; D013997:Time Factors
chemical_list: D017382:Reactive Oxygen Species