title: Exercise-induced oxidative DNA damage and lymphocytopenia in sedentary young males.
abstract: Post high-intensity exercise lymphocytopenia is well documented, but its underlying mechanisms have not been fully elucidated. A possible mechanism is a reactive oxygen species-induced DNA damage after high-intensity exercise. Furthermore, lymphocyte apoptosis related to DNA damage might contribute to exercise-induced lymphocytopenia.
  
  
  OBJECTIVE
  This study examined lymphocytopenia, lymphocyte oxidative DNA damage, and apoptosis in young healthy sedentary males after acute high-intensity exercise.
  
  
  METHODS
  Fifteen subjects exercised on bicycle ergometers for 1 h at 75% of their VO2max. Venous blood samples were taken before exercise (PRE) and hourly after exercise until 4 h (P0-P4). Lymphocyte counts, oxidative DNA damage evaluated using the Comet assay with human 8-oxoguanine DNA glycosylase, and serum lipid peroxide (LPO) concentration were measured. Furthermore, lymphocyte superoxide, Fas receptor (CD95), and Annexin-V-positive lymphocyte apoptosis cells were measured in 10 subjects who exercised and gave blood samples as described above.
  
  
  RESULTS
  Lymphocyte counts became significantly lower than the PRE value (P < 0.05): 20.4% at P1, 24.3% at P2, and 16.3% at P3. Moreover, LPO significantly increased by P2 (P < 0.05): 1.6-fold. The % DNA in tail, indicating oxidative DNA damage, was significantly higher at P3 (54.3 +/- 12.8%) than at PRE (42.6 +/- 11.1%, P < 0.05). The lymphocyte superoxide level was significantly higher (51.3%) than the PRE value (P < 0.05). Neither CD95 nor Annexin-V-positive cells were significantly different than the PRE value.
  
  
  CONCLUSIONS
  Results of this study suggest that lymphocyte oxidative DNA damage can relate to lymphocytopenia, although DNA damage was not associated with apoptosis in healthy young sedentary males.
authors.affiliation: Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaraki, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Tanimura
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Shimizu
authors.forename: Kai
authors.initials: K
authors.lastname: Tanabe
authors.forename: Takeshi
authors.initials: T
authors.lastname: Otsuki
authors.forename: Ryohei
authors.initials: R
authors.lastname: Yamauchi
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Matsubara
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Iemitsu
authors.forename: Seiji
authors.initials: S
authors.lastname: Maeda
authors.forename: Ryuichi
authors.initials: R
authors.lastname: Ajisaka
mesh_terms: D000328:Adult; D004249:DNA Damage / Q000276:immunology*; D005080:Exercise Test; D006801:Humans; D008231:Lymphopenia / Q000097:blood / Q000235:genetics; D008297:Male; D018384:Oxidative Stress / Q000235:genetics*; D010101:Oxygen Consumption; D005082:Physical Exertion / Q000502:physiology*; D017382:Reactive Oxygen Species
chemical_list: D017382:Reactive Oxygen Species