title: Hsp72 and Hsp90α mRNA transcription is characterised by large, sustained changes in core temperature during heat acclimation.
abstract: Increased intracellular heat shock protein-72 (Hsp72) and heat shock protein-90α (Hsp90α) have been implicated as important components of acquired thermotolerance, providing cytoprotection during stress. This experiment determined the physiological responses characterising increases in Hsp72 and Hsp90α mRNA on the first and tenth day of 90-min heat acclimation (in 40.2 °C, 41.0 % relative humidity (RH)) or equivalent normothermic training (in 20 °C, 29 % RH). Pearson's product-moment correlation and stepwise multiple regression were performed to determine relationships between physiological [e.g. (Trec, sweat rate (SR) and heart rate (HR)] and training variables (exercise duration, exercise intensity, work done), and the leukocyte Hsp72 and Hsp90α mRNA responses via reverse transcription quantitative polymerase chain reaction (RT-QPCR) (n = 15). Significant (p < 0.05) correlations existed between increased Hsp72 and Hsp90α mRNA (r = 0.879). Increased core temperature was the most important criteria for gene transcription with ΔTrec(r = 0.714), SR (r = 0.709), Trecfinal45(r = 0.682), area under the curve where Trec≥ 38.5 °C (AUC38.5 °C; r = 0.678), peak Trec(r = 0.661), duration Trec≥ 38.5 °C (r = 0.650) and ΔHR (r = 0.511) each demonstrating a significant (p < 0.05) correlation with the increase in Hsp72 mRNA. The TrecAUC38.5 °C (r = 0.729), ΔTrec(r = 0.691), peak Trec(r = 0.680), Trecfinal45(r = 0.678), SR (r = 0.660), duration Trec≥ 38.5 °C (r = 0.629), the rate of change in Trec(r = 0.600) and ΔHR (r = 0.531) were the strongest correlate with the increase in Hsp90α mRNA. Multiple regression improved the model for Hsp90α mRNA only, when TrecAUC38.5 °C and SR were combined. Training variables showed insignificant (p > 0.05) weak (r < 0.300) relationships with Hsp72 and Hsp90α mRNA. Hsp72 and Hsp90α mRNA correlates were comparable on the first and tenth day. When transcription of the related Hsp72 and Hsp90α mRNA is important, protocols should rapidly induce large, prolonged changes in core temperature.
authors: Centre for Human Performance, Exercise and Rehabilitation (CHPER), Brunel University London, Uxbridge, UK. oliver.gibson@brunel.ac.uk.|Centre for Sport and Exercise Science and Medicine (SESAME), Environmental Extremes Laboratory, Welkin Human Performance Laboratories, University of Brighton, Denton Road, Eastbourne, UK. oliver.gibson@brunel.ac.uk.
authors: Oliver R
authors: OR
authors: Gibson
authors: Muscle Cellular and Molecular Physiology (MCMP) and Applied Sport and Exercise Science (ASEP) Research Groups, Institute of Sport and Physical Activity Research (ISPAR), University of Bedfordshire, Bedford, UK.
authors: James A
authors: JA
authors: Tuttle
authors: Centre for Sport and Exercise Science and Medicine (SESAME), Environmental Extremes Laboratory, Welkin Human Performance Laboratories, University of Brighton, Denton Road, Eastbourne, UK.
authors: Peter W
authors: PW
authors: Watt
authors: Centre for Sport and Exercise Science and Medicine (SESAME), Environmental Extremes Laboratory, Welkin Human Performance Laboratories, University of Brighton, Denton Road, Eastbourne, UK.
authors: Neil S
authors: NS
authors: Maxwell
authors: Athlete Health and Performance Research Centre, ASPETAR, Qatar Orthopaedic and Sports Medicine Hospital, Doha, Qatar.|School of Sport, Exercise and Health Sciences, Loughborough University, Loughborough, UK.
authors: Lee
authors: L
authors: Taylor
mesh_terms: D000328:Adult; D019540:Area Under Curve; D015444:Exercise; D050884:HSP72 Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D018841:HSP90 Heat-Shock Proteins / Q000235:genetics* / Q000378:metabolism; D006339:Heart Rate; D006801:Humans; D007962:Leukocytes / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism*; D012372:ROC Curve; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013542:Sweat / Q000378:metabolism; D013696:Temperature; D014158:Transcription, Genetic; D055815:Young Adult
chemical_list: D050884:HSP72 Heat-Shock Proteins; D018841:HSP90 Heat-Shock Proteins; C533585:HSP90AA2P protein, human; D012333:RNA, Messenger
keywords: Core temperature; Heat acclimation; Heat shock proteins; Hyperthermia; Thermotolerance