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- Title
Free-radical production triggered by hyperthermia contributes to heat stress-induced cardioprotection in isolated rat hearts.
- Authors
Arnaud, Claire; Joyeux, Marie; Carrel, Catherine; Godin-Ribuot, Diane; Demenge, Pierre; Ribuot, Christophe
- Abstract
1 Heat stress (HS) is known to protect the myocardium against ischacmic damage. It has been reported that reactive oxygen species (ROS) arc abundantly produced during this stress. Since mechanisms triggering the HS-induced cardioprotection remain unknown, we investigated the role of ROS in the genesis of this protective phenomenon. 2 Rats were divided into four groups (n= 8 in each group), subjected to either hyperthermia (42 C internal temperature for 15 min) or sham anaesthesia and treated or not with N′-2-mercaptopro-pionyl glycine (MPG), a synthetic antioxidant, 10 min before HS. Twenty-four hours later, their hearts were isolated, retrogradely perfused, and subjected to a 30-min occlusion of the left coronary artery followed by 120 min of repcrfusion. Myocardial Hsp 27 and 70 expression was assessed by Western blot analysis (n&asymp4}. Cardiac activities of antioxidant, enzymes (superoxide dismutase and glutathione peroxidase) were also examined (n=4). 3 Infarct-to-risk one ratio was significantly reduced in HS (17±13%) compared to Sham <34.3± 1.7%) hearts. This effect was abolished by MPG pretreatment (40.6± 1,9% in HS+ MPG vs 39,8±2,5% in Sham + MPG hearts). This cardioprotection was associated with an enhanced Hsp 27 and 70 expression, which was not modified by MPG preireatment. Antioxidant enzyme activities was not modified by heat stress or MPG pretreatment. 4 Free radical production following hyperthermia appears to play a role in the heat stress induced cardioprotection, independently of Hsp levels, Antioxidant enzyme activities do not seem to be implicated in this cardioprotective mechanism.
- Subjects
PHYSIOLOGICAL effects of heat; CARDIOVASCULAR system; HEAT shock proteins; FREE radicals; ANIMAL models in research
- Publication
British Journal of Pharmacology, 2002, Vol 135, Issue 7, p1776
- ISSN
0007-1188
- Publication type
Article
- DOI
10.1038/sj.bjp.0704619