title: The antioxidant enzyme peroxiredoxin-2 is depleted in lymphocytes seven days after ultra-endurance exercise.
abstract: OBJECTIVE
  Peroxiredoxin-2 (PRDX-2) is an antioxidant and chaperone-like protein critical for cell function. This study examined whether the levels of lymphocyte PRDX-2 are altered over 1 month following ultra-endurance exercise.
  
  
  METHODS
  Nine middle-aged men undertook a single-stage, multi-day 233 km (145 mile) ultra-endurance running race. Blood was collected immediately before (Pre), upon completion/retirement (Post), and following the race at Day 1, Day 7 and Day 28. Lymphocyte lysates were examined for PRDX-2 by reducing and non-reducing SDS-PAGE with western blotting. In a sub-group of men who completed the race (n = 4), PRDX-2 oligomeric state (indicative of redox status) was investigated.
  
  
  RESULTS
  Ultra-endurance exercise caused significant changes in lymphocyte PRDX-2 (F(4,32) 3.409, p = 0.020, η(2) = 0.299): 7 days after the race, PRDX-2 levels in lymphocytes had fallen to 30% of pre-race values (p = 0.013) and returned to near-normal levels at Day 28. Non-reducing gels demonstrated that dimeric PRDX-2 (intracellular reduced PRDX-2 monomers) was increased in three of four race completers immediately post-race, indicative of an 'antioxidant response'. Moreover, monomeric PRDX-2 was also increased immediately post-race in two of four race-completing subjects, indicative of oxidative damage, which was not detectable by Day 7.
  
  
  CONCLUSIONS
  Lymphocyte PRDX-2 was decreased below normal levels 7 days after ultra-endurance exercise. Excessive accumulation of reactive oxygen species induced by ultra-endurance exercise may underlie depletion of lymphocyte PRDX-2 by triggering its turnover after oxidation. Low levels of lymphocyte PRDX-2 could influence cell function and might, in part, explain reports of dysregulated immunity following ultra-endurance exercise.
authors.affiliation: Department for Health, University of Bath , Bath , UK.
authors.forename: J E
authors.initials: JE
authors.lastname: Turner
authors.forename: S J
authors.initials: SJ
authors.lastname: Bennett
authors.forename: J P
authors.initials: JP
authors.lastname: Campbell
authors.forename: J A
authors.initials: JA
authors.lastname: Bosch
authors.forename: S
authors.initials: S
authors.lastname: Aldred
authors.forename: H R
authors.initials: HR
authors.lastname: Griffiths
mesh_terms: D015444:Exercise / Q000502:physiology*; D006801:Humans; D008214:Lymphocytes / Q000201:enzymology*; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress / Q000502:physiology; D054464:Peroxiredoxins / Q000097:blood*; D010807:Physical Endurance / Q000502:physiology*
chemical_list: D054464:Peroxiredoxins