In vivo heat shock preconditioning mitigates calcium overload during ischaemia/reperfusion in the isolated, perfused rat heart.
Heat shock (HS) pretreatment of the heart is effective in mitigating the deleterious effects of ischaemia/reperfusion. The main objective of this study was to determine whether the beneficial effect of HS is associated with the preservation of intracellular Ca2+ handling in the ischaemic/reperfused, isolated rat heart. Twenty-four hours after raising body core temperature to 42 degrees C for 15 min, rat hearts were perfused according to Langendorff and subjected to 30 min ischaemia followed by 20 min reperfusion. Cyclic changes of cytoplasmic calcium ion [Ca2+i] levels were measured by surface fluorometry using Indo-1 AM. Reperfused HS hearts showed improved recovery of contractile function compared with control hearts: end-diastolic pressure: 45+/-11 vs. 64+/-22 mmHg; developed pressure: 72+/-12 vs. 41+/-20 mmHg; maximum rate of pressure increase (+dP/dtmax): 1,513+/-305 vs. 938+/-500 mmHg/s; maximum rate of pressure decrease (-dP/dtmax): -1,354+/-304 vs. -806+/-403 mmHg/s. HS hearts displayed a significantly lower end-diastolic cytosolic [Ca2+] ([Ca2+]i) after reinstallation of flow. The dynamic parameters of the Ca2+i transients, i.e. the maximum rate of increase/decrease (+/-dCa2+i/dtmax) and amplitude, did not differ between reperfused control and HS hearts. The novel finding of this study is that improved performance of the HS-preconditioned heart after an ischaemic insult is associated with a reduced end-diastolic Ca2+i load, and most likely, preserved Ca2+ sensitivity of the myocardial contractile machinery.
Szenczi
Orsolya
O
Institute of Human Physiology and Clinical Experimental Research, Semmelweis University, Ulloi út 78/A, 1082, Budapest, Hungary.
Kemecsei
Péter
P
Miklós
Zsuzsanna
Z
Ligeti
László
L
Snoeckx
Luc H E H
LH
van Riel
Natal A W
NA
Op den Buijs
Jorn
J
Van der Vusse
Ger J
GJ
Ivanics
Tamás
T
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D003971:Diastole / Q000502:physiology; D018840:HSP70 Heat-Shock Proteins / Q000378:metabolism; D006321:Heart / Q000502:physiology*; D018869:Heat-Shock Response / Q000502:physiology*; D019194:Ischemic Preconditioning; D008297:Male; D009206:Myocardium / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D015427:Reperfusion Injury / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control*; D017725:Ventricular Pressure / Q000502:physiology
D018840:HSP70 Heat-Shock Proteins; D002118:Calcium