Ischaemic preconditioning but not isoflurane prevents post-ischaemic production of hydroxyl radicals in a canine model of ischaemia-reperfusion.
OBJECTIVE
Isoflurane has been shown to mimic ischaemic preconditioning (IPC). The protective effect of IPC, or applying isoflurane or perfusion with the 'push-pull' complex zinc-desferrioxamine (Zn-DFO) in the canine heart, was investigated.


METHODS
Thirty minutes after salicylate administration (100 mg kg(-1)) the heart was exposed. All dogs were subjected to a 10 min left anterior descending artery occlusion followed by 2 h of reperfusion. In Group I (n = 9) isoflurane (2.5%) was administered 10 min prior to and during ischaemia. In Group II (n = 8), IPC was elicited by 5 min coronary artery occlusion, followed by 5 min of reperfusion, prior to the 10 min ischaemia. In Group III (n = 9) Zn-DFO (2.5 mg kg(-1)) was given 10 min prior to ischaemia. The effects of these interventions were compared to control (n = 10). Coronary sinus blood concentrations of salicylate, 2,3-dihydroxybenzoic acid (DHBA), lactate, pH and oxygen content were monitored.


RESULTS
In the control group, 2,3-DHBA increased by 32% above the pre-ischaemic value (P < 0.05). In contrast, in the IPC hearts, a significant decrease in the production of 2,3-DHBA was observed (40% lower than baseline, P < 0.01). In the isoflurane group only a 13% (and non-significant) decrease was noticed. In the Zn-DFO group a 33% decrease was found (P < 0.01). The increase in lactate concentrations in the IPC and Zn-DFO groups was significantly smaller than that of control and isoflurane groups.


CONCLUSIONS
IPC protected the heart against the deleterious effects of reperfusion, possibly by amelioration of the level of oxygen-derived reactive species, and the complete inhibition of reactive hydroxyl radical production. Isoflurane did not prove to be as effective in reducing the free radical damage.
Gozal
Y
Y
Hadassah University Hospital, Hebrew University Faculty of Medicine, Department of Anesthesiology and CCM, Jerusalem, Israel. gozaly@md2.huji.ac.il
Chevion
M
M
Elami
A
A
Berenshtein
E
E
Kitrossky
N
N
Drenger
B
B
D018685:Anesthetics, Inhalation / Q000627:therapeutic use*; D000818:Animals; D000931:Antidotes / Q000627:therapeutic use; D001794:Blood Pressure / Q000187:drug effects; D002396:Catechols / Q000494:pharmacology; D003676:Deferoxamine / Q000627:therapeutic use; D004285:Dogs; D006339:Heart Rate / Q000187:drug effects; D006863:Hydrogen-Ion Concentration; D062385:Hydroxybenzoates; D017665:Hydroxyl Radical / Q000378:metabolism*; D019157:Ischemic Preconditioning, Myocardial; D007530:Isoflurane / Q000627:therapeutic use*; D019344:Lactic Acid / Q000378:metabolism; D015428:Myocardial Reperfusion Injury / Q000517:prevention & control*; D009206:Myocardium / Q000378:metabolism; D010101:Oxygen Consumption / Q000187:drug effects; D012459:Salicylates
D018685:Anesthetics, Inhalation; D000931:Antidotes; D002396:Catechols; D062385:Hydroxybenzoates; D012459:Salicylates; D017665:Hydroxyl Radical; D019344:Lactic Acid; C009135:2,3-dihydroxybenzoic acid; D007530:Isoflurane; D003676:Deferoxamine