Diabetes mellitus attenuates myocardial preconditioning of desflurane in ischemia-reperfused rat heart

Desflurane has been commonly used in anesthesia that possesses a cardioprotective effect against ischemia-reperfusion. We evaluated whether diabetes mellitus affected desflurane preconditioning induced cardioprotection in ischemia-reperfusion rat hearts in view of pro- and anti-apoptotic signaling pathways and Ca²⁺ homeostasis. Streptozotocin-induced, diabetic rats and age-matched wild-type Sprague-Dawley rats were subjected to a left anterior descending coronary artery occlusion for 30 min followed by 1 hr of reperfusion. Myocardial infarct size, activities of Akt, ERK1/2, Bcl-2, Bax and cytochrome c, and gene expression influencing Ca²⁺ homeostasis were examined. Desflurane preconditioning significantly reduced myocardial infarct size compared to ischemia-reperfusion in wild-type rats but not in diabetic rats. In addition, decrease in Akt, ERK1/2, and Bcl-2, and the increase in Bax and cytochrome c by ischemia-reperfusion was reduced by desflurane preconditioning. In diabetic rat hearts, however, desflurane preconditioning failed to recover the phosphorylation state of Akt and ERK1/2 and to repress apoptotic signaling in association with impoverished modulation of abnormal changes in sarcoplasmic reticulum proteins in ischemia-reperfusion rat hearts. These results suggest that diabetes mellitus attenuated desflurane preconditioning against ischemia-reperfusion, which might be associated with reduced recovery of the activities of proteins involved in anti-apoptotic signaling pathways and sarcoplasmic reticulum.