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This Article Full Text Full Text (PDF) All Versions of this Article: 292/4/H1986    most recent 01214.2006v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Web of Science (7) Citing Articles via Google Scholar Google Scholar Articles by Makazan, Z. Articles by Dhalla, N. S. Search for Related Content PubMed PubMed Citation Articles by Makazan, Z. Articles by Dhalla, N. S.

Role of oxidative stress in alterations of mitochondrial function in ischemic-reperfused hearts

Institute of Cardiovascular Sciences, St. Boniface General Hospital Research Centre, and Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada

Submitted 3 November 2006 ; accepted in final form 11 December 2006

To study the mechanisms of mitochondrial dysfunction due to ischemia-reperfusion (I/R) injury, rat hearts were subjected to 20 or 30 min of global ischemia followed by 30 min of reperfusion. After recording both left ventricular developed pressure (LVDP) and end-diastolic pressure (LVEDP) to monitor the status of cardiac performance, mitochondria from these hearts were isolated to determine respiratory and oxidative phosphorylation activities. Although hearts subjected to 20 min of ischemia failed to generate LVDP and showed a marked increase in LVEDP, no changes in mitochondrial respiration and phosphorylation were observed. Reperfusion of 20-min ischemic hearts depressed mitochondrial function significantly but recovered LVDP completely and lowered the elevated LVEDP. On the other hand, depressed LVDP and elevated LVEDP in 30-min ischemic hearts were associated with depressions in both mitochondrial respiration and oxidative phosphorylation. Reperfusion of 30-min ischemic hearts elevated LVEDP, attenuated LVDP, and decreased mitochondrial state 3 and uncoupled respiration, respiratory control index, ADP-to-O ratio, as well as oxidative phosphorylation rate. Alterations of cardiac performance and mitochondrial function in I/R hearts were attenuated or prevented by pretreatment with oxyradical scavenging mixture (superoxide dismutase and catalase) or antioxidants [N-acetyl-L-cysteine or N-(2-mercaptopropionyl)-glycine]. Furthermore, alterations in cardiac performance and mitochondrial function due to I/R were simulated by an oxyradical-generating system (xanthine plus xanthine oxidase) and an oxidant (H₂O₂) either upon perfusing the heart or upon incubation with mitochondria. These results support the view that oxidative stress plays an important role in inducing changes in cardiac performance and mitochondrial function due to I/R.

cardiac performance; oxidative phosphorylation; mitochondrial respiration; oxyradicals; antioxidants

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