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Isothermic and fixed‐intensity heat acclimation methods elicit equal increases in Hsp72 mRNA
Author(s) -
Gibson O. R.,
Mee J. A.,
Taylor L.,
Tuttle J. A.,
Watt P. W.,
Maxwell N. S.
Publication year - 2015
Publication title -
scandinavian journal of medicine and science in sports
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.575
H-Index - 115
eISSN - 1600-0838
pISSN - 0905-7188
DOI - 10.1111/sms.12430
Subject(s) - acclimatization , messenger rna , endogeny , heat shock protein , transcription (linguistics) , shock (circulatory) , biology , heat stress , real time polymerase chain reaction , heat shock , andrology , zoology , medicine , endocrinology , biochemistry , genetics , gene , linguistics , philosophy
Thermotolerance, to which heat shock protein‐72 ( Hsp72 ) contributes, is an acquired state achieved following heat acclimation ( HA ), eliciting cellular adaption and protection against thermal stress. Optimal HA methods achieving the greatest heat shock response ( HSR ) are equivocal; therefore, investigation of methods provoking the greatest sustained HSR is required to optimize cellular adaptation. Twenty‐four males performed short‐term HA ( STHA ; five sessions) and long‐term HA ( LTHA ; STHA plus further five sessions) utilizing fixed‐intensity ( FIXED ; workload = 50%V ˙ O 2 p e a k), continuous isothermic HA [ ISO CONT ; target rectal temperature ( T rec ) = 38.5 °C], or progressive isothermic HA ( ISO PROG ; target T rec = 38.5 °C for STHA then target T rec = 39.0 °C for LTHA ). Leukocyte Hsp72 mRNA was measured pre‐ and post day 1, day 5, and day 10 of HA via reverse transcription quantitative polymerase chain reaction to determine the HSR . Hsp72 mRNA increased ( P < 0.05) pre‐ to post day 1, pre‐ to post day 5, and pre to post day 10 in FIXED , ISO CONT , and ISO PROG , but no differences were observed between methods ( P > 0.05). The equal Hsp72 mRNA increases occurring from consistent, reduced, or increased endogenous strain following STHA and LTHA suggest that transcription occurs following attainment of sufficient endogenous criteria. These data give confidence that all reported HA methods increase Hsp72 mRNA and are capable of eliciting adaptations toward thermotolerance.