阿片受体在异氟醚延迟预处理减轻兔心肌缺血再灌注损伤中的作用

Objective To investigate the role of opioid receptors in the protective effects of isoflurane-induced delayed preconditioning against myocardial ischemia-reperfusion (I/R) injury in rabbits. Methods Forty male New Zealand white rabbits weighing 2.0-2.5 kg were randomly assigned into 4 groups ( n = 10 each) : group I sham operation (S); group II I/R; group Ⅲ isoflurane + I/R (Iso) and group IV Iso + naloxone + I/R (Nal). Myocardial I/R was induced by 40 min occlusion of left anterior descending branch (LAD) of coronary artery followed by 120 min reperfusion. In group Ⅲ (Iso) 2% isoflurane in 100% O2 was inhaled for 2 h and I/R was produced 24 h later. In group IV (Nal) naloxone 6 mg/kg was given iv 10 min before 2 h of 2% isoflurane inhalation and I/R was produced 24 h later. At the end of 120 min reperfusion, infarct size (IS) and area at risk (AAR) were determined by Evan's blue and TTC staining. Myocardial ultrastructure was examined by electron microscopy. The phosphorylated p38MAPK protein expression in myocardium was determined by Western blot. Results The IS was significantly smaller in group Iso ( Ⅲ ) ( 19.7% ± 2.8%) than in I/R group ( II ) (37.8% ±1.7%) (P<0.05). The phosphorylated p38MAPK protein expression in myocardium was significantly lower in group Iso than in group I/R. Microscopic examination showed less myocardial damage in Iso group than in group I/R. The protective effects of delayed preconditioning by isoflurane was prevented by naloxone pretreatment. ConclusionOpioid receptors may be involved in the protective effects of delayed preconditioning by isoflurane against myocardial I/R injury.

Role of opioid receptors in protective effects of isoflurane- induced delayed preconditioning against myocardial ischemia-reperfusion injury in rabbits