Deep hypothermia during ischemia improves functional recovery and reduces free-radical generation in isolated reperfused rat heart.
BACKGROUND
We investigated the influence of deep hypothermia (4 degrees C) during ischemia-reperfusion in the isolated rat heart model.


METHODS
Isolated, perfused rat hearts underwent either 30 minutes of normothermic ischemia (control group) or 30 minutes of hypothermic ischemia (hypothermia-treated group), followed by 30 minutes of reperfusion in both groups. We recorded functional parameters and used electron spin resonance (ESR) spectroscopy to detect ascorbyl radicals, as markers of free-radical production, in samples of coronary effluents.


RESULTS
Functional parameters were stable in the 2 groups during pre-ischemic and ischemic periods. During reperfusion, coronary flow, left diastolic ventricular pressure, left ventricular developed pressure, and heart rate more rapidly recovered to values close to those obtained during the pre-ischemic period in the hypothermia-treated group than in the control group. Moreover, the post-ischemic contracture observed in the control group did not appear in the hypothermia-treated group. Finally, ESR analysis showed that the post-ischemic release of ascorbyl radicals decreased in the hypothermia-treated group.


CONCLUSIONS
These results demonstrate that the protective effect of hypothermia against functional injury caused by ischemia-reperfusion may decrease the free-radical burst at reperfusion.
Gambert
Ségolène
S
Laboratory of Cardiovascular Pathophysiology and Pharmacology of the Institut Fédératif de Recherche, Institute of Cardiovascular Research, University Hospital Center, Dijon, France.
Bès-Houtmann
Sandrine
S
Vandroux
David
D
Tissier
Cindy
C
Vergely-Vandriesse
Catherine
C
Rochette
Luc
L
Athias
Pierre
P
D000818:Animals; D003326:Coronary Circulation / Q000502:physiology*; D003683:Dehydroascorbic Acid / Q000031:analogs & derivatives* / Q000378:metabolism*; D004195:Disease Models, Animal; D004578:Electron Spin Resonance Spectroscopy; D007036:Hypothermia, Induced; D017202:Myocardial Ischemia / Q000378:metabolism* / Q000628:therapy*; D051381:Rats; D017208:Rats, Wistar; D020127:Recovery of Function / Q000502:physiology; D015427:Reperfusion Injury / Q000517:prevention & control*; D017725:Ventricular Pressure / Q000502:physiology
C000820:semidehydroascorbic acid; D003683:Dehydroascorbic Acid