The efficacy of
endothelin receptor antagonists in protecting against
myocardial ischemia/reperfusion (I/R) injury is controversial, and the mechanisms remain unclear. The aim of this study was to investigate the effects of CPU0123, a novel
endothelin type A and type B receptor antagonist, on myocardial I/R injury and to explore the mechanisms involved. Male Sprague-Dawley rats weighing 200-250 g were randomized to three groups (6-7 per group): group 1,
Sham; group 2, I/R + vehicle. Rats were subjected to in vivo myocardial I/R injury by
ligation of the left anterior descending coronary artery and 0.5%
sodium carboxymethyl cellulose (1 mL/kg) was injected intraperitoneally immediately prior to
coronary occlusion. Group 3, I/R +
CPU0213. Rats were subjected to identical
surgical procedures and
CPU0213 (30 mg/kg) was injected intraperitoneally immediately prior to
coronary occlusion.
Infarct size, cardiac function and biochemical changes were measured.
CPU0213 pretreatment reduced
infarct size as a percentage of the ischemic area by 44.5% (I/R + vehicle: 61.3 ± 3.2
vs I/R +
CPU0213: 34.0 ± 5.5%, P < 0.05) and improved ejection fraction by 17.2% (I/R + vehicle: 58.4 ± 2.8
vs I/R +
CPU0213: 68.5 ± 2.2%, P < 0.05) compared to vehicle-treated animals. This protection was associated with inhibition of myocardial
inflammation and oxidative stress. Moreover, reduction in Akt (
protein kinase B) and
endothelial nitric oxide synthase (eNOS) phosphorylation induced by myocardial I/R injury was limited by
CPU0213 (P < 0.05). These data suggest that CPU0123, a non-selective antagonist, has protective effects against myocardial I/R injury in rats, which may be related to the Akt/eNOS pathway.