Published online by Cambridge University Press: 13 April 2005
Summary
Background and 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.