Nuclear factor (NF)KB activation in human peripheral blood mononuclear cells of trained versus untrained individuals during exertional heat stress

Par Conseil national de recherches du Canada

DOI	Trouver le DOI : https://doi.org/10.1249/01.mss.0000273139.54027.b5
Auteur	Rechercher : Selkirk, Glen A.; Rechercher : Wright, Heather E.; Rechercher : McLellan, Tom M.; Rechercher : Rhind, Shawn G.
Format	Texte, Allocution
Conférence	54th Annual Meeting of the American College of Sports Medicine (ACSM), May30th-June 2nd, 2007, New Orleans, Louisiana
Résumé	Inflammatory responses are regulated by transcription factor NF-KB, predominately inactive in the cytoplasm. Upon activation, NF-KB translocation into the nucleus regulates gene transcription of pro inflammatory cytokines. PURPOSE: The purpose of this study was to examine the effect of a single bout of exertional heat stress (EHS) on NF-?B DNA-binding in human peripheral blood mononuclear cells (PBMC) of trained (TR) and untrained (UT) individuals. METHODS: Maximum oxygen consumption expressed per kg of lean body mass (LBM) and activity history was used to divide subjects into TR (n=12, VO2peak= 70 ± 2 mL-kgLBM-l-mm-1) and UT (n=10, VO2peak= 50 ± 1 mL-kgLBM-l-mm-1) groups. Subjects walked at 4.5 km-h-1 with 2% elevation in a climatic chamber (40°C; 30% R.H.) wearing military biological and chemical protective clothing until specific end-point criteria were attained. Venous blood samples were collected at baseline (B), rectal temperatures of 38.0°C, 38.5°C, 39.0°C and at exhaustion (Exh). Whole blood was analysed by flow cytometry for intranuclear inflammatory transcription factor NF-KB in PBMC. Similar analyses were performed following in vitro lipopolysacharide (LPS) stimulation (30 min,100ng/mL). RESULTS: Rectal temperature (Tre) tolerated at Exh was higher in TR (39.7 ± 0.1 °C) compared to UT (39.1 ± 0.1°C), however, the rate of Tre increase was not significantly different between the groups (1.0 ± 0.05 °C/hr). Exertional heat stress induced a temperature dependent elevation in the absolute count (x109cell/L) of PBMC expressing NF-KB in TR and UT compared to B. Intranuclear NF-KB relative mean fluorescence intensity (MFI) was elevated compared to B in both TR and UT at 38.5°C and in TR at 39.5°C. At Exh, intranuclear NF-KB DNA-binding was not significantly different from B in vivo. Additional in vitro LPS stimulation induced a significantly greater increase in NF-KB DNA-binding from B compared to Exh. CONCLUSIONS: These findings suggest that the observed upregulation of intranuclear NF-KB in circulating PBMC during EHS may be attributed to both leukocyte mobilization and/or NF-KB translocation. Although there were no significant differences observed between TR and UT up to 39.0°C, EHS was found to increase LPS tolerance upon stimulation in vitro.
Date de publication	2007-06-02
Maison d’édition	American College of Sports Medicine / Wolters Kluwer
Dans	Medicine and Science in Sports and Medicine 39, nº 5 Suppl. : S61–S61.
Langue	anglais
Publications évaluées par des pairs	Oui
Publication du CNRC	Cette publication n’est pas du CNRC Ce sont des publications qui ont été rédigées par un auteur du CNRC, mais avant que celui-ci soit employé du CNRC.
Numéro NPARC	23001426
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Identificateur de l’enregistrement	393ebe5c-abdf-40c3-b504-3d55b782a4bf
Enregistrement créé	2017-02-03
Enregistrement modifié	2020-03-03

Date de modification :: 2024-12-21