Repeated non-invasive remote ischemic preconditioning confers cardioprotection in diabetic rats

Abstract

Non-invasive Remote ischemic preconditioning (NRIPC) has a cardioprotective effect in normal rats, but its effect in rats with diabetes is controversial. This study was mainly to determine the cardioprotective effect of NRIPC on ischemia reperfusion injury (IRI) in diabetic rats. Diabetes was induced in Sprague-Dawley rats with streptozotocin. NRIPC was implemented by applying 3 cycles of 5-min occlusion/5-min reperfusion in a unilateral hindlimb once per day for three days. The animals were then subjected to 30 minutes of coronary artery occlusion followed by two hours of reperfusion. A control group had no NRIPC. The results showed that NRIPC significantly reduced post-ischemic myocardial infarct size,lactate dehydrogenase (LDH) and troponin-1 release during reperfusion in both control and diabetic rats. Protein PKC-ε, phosphorylation of AKT and signal transducer and activator of transcription 3(STAT3) were all significantly increased after NRIPC and their enhancement after reperfusion was correlated with reductions of post-ischemic myocardial infarction and cellular injury. In conclusion, cardioprotection can be achieved in diabetes by NRIPC applied repeatedly for three days prior to inducing myocardial infarction and activation of PKC-ε and STAT3 might be a major mechanism of NRIPC protection.