title: Leukocyte apoptosis and pro-/anti-apoptotic proteins following downhill running.
abstract: The purposes of this study were to determine the effect of eccentric exercise-induced muscle damage on the induction of apoptosis in peripheral blood leukocytes and to investigate if the elevation in apoptotic leukocytes was mediated by changes in the concentration of anti-/pro-apoptotic proteins in circulation. Twelve moderately trained subjects performed three 40 min treadmill runs at ~70% VO(2max): a level run (L) followed by two downhill runs (DH1 and DH2). Blood samples were taken at rest (PRE) and immediately (POST), 2, 24, and 48 h after each run. Data were analyzed using two-way repeated measures analysis of variance with post hoc Tukey tests. Creatine kinase (CK) activity was significantly elevated at 24 and 48 h following DH1 (P < 0.01). The proportion (%) of apoptotic leukocytes was significantly elevated at POST and 2 h following all three runs, and up to 48 h following DH1 (P < 0.01). Bax at 24-h post and Bax/Bcl-2 ratio at 24- (P < 0.01) and 48-h post (P < 0.05) following DH1 were greater than PRE (P < 0.05). An acute bout of moderate intensity downhill running altered CK activity, Bax concentration and the Bax/Bcl-2 ratio in circulating leukocytes resulting in a greater apoptotic response at 24- and 48-h post-exercise compared to level grade running or a second downhill run. Although the mechanism by which these proteins are altered by unaccustomed eccentric exercise is currently unknown, the differential response to DH1 versus L and DH2 indicates that it may be related to exercise-induced muscle damage.
authors.affiliation: Fitness and Sports Program, Texas A&M International University, 5201 University Blvd, Laredo, TX 78041, USA. kpark@tamiu.edu
authors.forename: Kyung-Shin
authors.initials: KS
authors.lastname: Park
authors.forename: Darlene A
authors.initials: DA
authors.lastname: Sedlock
authors.forename: James W
authors.initials: JW
authors.lastname: Navalta
authors.forename: Man-Gyoon
authors.initials: MG
authors.lastname: Lee
authors.forename: Seung-Hwan
authors.initials: SH
authors.lastname: Kim
mesh_terms: D000293:Adolescent; D000328:Adult; D017209:Apoptosis / Q000502:physiology*; D051017:Apoptosis Regulatory Proteins / Q000032:analysis / Q000378:metabolism*; D003402:Creatine Kinase / Q000032:analysis / Q000378:metabolism; D005080:Exercise Test; D005260:Female; D006801:Humans; D007962:Leukocytes / Q000473:pathology / Q000502:physiology*; D008297:Male; D009051:Mountaineering / Q000502:physiology; D018482:Muscle, Skeletal / Q000378:metabolism / Q000502:physiology; D012420:Running / Q000502:physiology*; D055815:Young Adult
chemical_list: D051017:Apoptosis Regulatory Proteins; D003402:Creatine Kinase