Effect of isoflurane-induced delayed preconditioning on αB-crystallin expression during myocardial ischemia-reperfusion in rabbits

Objective To investigate the effect of isoflurane-induced delayed preconditioning on αB-crystallin expression during myocardial ischemia-reperfusion (I/R) in rabbits. Methods Thirty male New Zealand white rabbits weighing 2.0-2.5 kg were randomly assigned into 3 groups (n = 10 each):group Ⅰ sham operation (group S); group Ⅱ I/R and group Ⅲ Isoflurane + I/R (group Ise). 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, 2% isoflurane in 100% O2 was inhaled for 2 h and I/R was produced 24 h later. At the end of 120 min reperfusion, arterial blood samples were taken for determination of serum SOD activity. The animals were then killed and hearts removed for determination of αB-crystallin expression and caspase-3 expression. Infarct size and area at risk were determined by Evan's blue and TIC staining. Myocardial ultrastructure was examined by electron microscopy. Results The infarct size was significantly smaller, serum SOD activity significantly higher, caspase-3 expression significantly lower, and αB-crystallin expression significantly higher in group Iso than in group I/R (P < 0.05). Microscopic examination showed less myocardial damage in group lso than in group I/R. Conclusion The isoflurane-induced delayed preconditioning attenuates myocardial I/R injury possibly through up-regulating αB-crystallin expression in rabbits. Key words: Crystallins;  Isoflurane;  Ischemic preconditioning, myocardial;  Myocardial reperfusion injury