Heat shock protein 72 may improve hypotension by increasing cardiac mechanical efficiency and arterial elastance in heatstroke rats.
OBJECTIVE
We attempted to test the hypothesis that preinduction of heat shock protein (HSP) 72 in the heart would improve left ventricular performance in rat heatstroke.


METHODS
Cardiac expression of HSP 72 was quantitatively evaluated by western blot analysis in rats 0h, 12h, or 72h after mild heat preconditioning (MHP; 43°C for 30min). They were subjected to severe heat stress (SHS; 43°C for 70min) to induce heatstroke. A 1.2F catheter-tip pressure transducer was inserted into the left ventricle of these group rats under general anesthesia to record hemodynamic in the closed chest with a pressure-volume loop module data recording and analysis system.


RESULTS
At the time point of heatstroke onset, compared with normothermic controls, group rats with 12h post-MHP had significantly increased cardiac HSP 72, decreased hyperthermia, decreased hypotension, decreased bradycardia, increased end-systolic pressure, increased end-diastolic pressure, increased stroke volume, decreased end-systolic volume, decreased end-diastolic pressure, increased cardiac output, increased ejection fraction, increased stroke work, increased arterial elastance, and decreased time constant of fall in ventricular pressure by Glantz-methods. With the loss of cardiac HSP 72 expression observed at 72h in post-MHP group rats, an insignificant protection against left ventricular performance was observed.


CONCLUSIONS
Preinduction of cardiac HSP 72 may improve hypotension in heatstroke rats by increasing both cardiac mechanical efficiency and arterial elastance.
Department of Nursing, Shu-Zen Junior College of Medicine and Management, Kaohsiung City 821, Taiwan.
Shu-Fen
SF
Hsu
Department of Intensive Care Medicine, Chi Mei Medical Center, Liouying, Tainan 736, Taiwan.
Chien-Ming
CM
Chao
Department of Medical Research, Chi Mei Medical Center, Tainan 710, Taiwan; Department of Biotechnology, Southern Taiwan University of Science and Technology, Tainan 710, Taiwan.
Ching-Ping
CP
Chang
Department of Medical Research, Chi Mei Medical Center, Tainan 710, Taiwan.
Mao-Tsun
MT
Lin
Department of Biotechnology, Southern Taiwan University of Science and Technology, Tainan 710, Taiwan; Department of Surgery, Chi Mei Medical Center, Tainan 710, Taiwan. Electronic address: cbcheng@stust.edu.tw.
Bor-Chih
BC
Cheng
D000818:Animals; D001794:Blood Pressure / Q000502:physiology*; D050884:HSP72 Heat-Shock Proteins / Q000096:biosynthesis*; D006339:Heart Rate / Q000502:physiology*; D018883:Heat Stroke / Q000378:metabolism* / Q000503:physiopathology; D007022:Hypotension / Q000378:metabolism* / Q000503:physiopathology; D008297:Male; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013318:Stroke Volume / Q000502:physiology; D016277:Ventricular Function, Left / Q000502:physiology*
D050884:HSP72 Heat-Shock Proteins
Arterial elastance; Cardiac contractility; Heat shock protein 72; Hypotension