Role of class Ⅰ histone deacetylase in myocardial ischemia-reperfusion injury in diabetic rats and the relationship with AMPK∕mTOR signaling pathway / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the role of classⅠhistone deacetylase (HDAC) in myocardial ischemia-reperfusion (I∕R) injury in diabetic rats and the relationship with adenosine monophosphate-acti- vated protein kinase (AMPK)∕mammalian target of rapamycin (mTOR) signaling pathway. Methods SPF healthy adult male Sprague-Dawley rats, weighing 210-220 g, were used in this study. Type I diabetes mellitus was induced by single intraperitoneal injection of streptozotocin dissolved in citrate buffer 60 mg∕kg, and 8 weeks later the rats with type I diabetes mellitus were used for experiment. Forty-eight diabetic rats were divided into 4 groups (n＝12 each) by using a random number table method: sham operation group (group S), myocardial I∕R group (group I∕R), myocardial I∕R plus class I HDAC inhibitor MS-275 group (group I∕R+MS) and myocardial I∕R plus MS-275 plus AMPK inhibitor Compound C group ( group I∕R+MS+CC). Myocardial I∕R was induced by ligation of the left anterior descending branch of the coronary ar-tery for 45 min followed by 180 min of reperfusion in anesthetized rats. In group I∕R+MS, MS-275 10 mg∕kg was intraperitoneally injected once a day for 7 consecutive days, and myocardial I∕R was produced after the end of administration. AMPK inhibitor Compound C 0. 5 mg∕kg was intravenously injected at 30 min before ischemia in group I∕R+MS+CC. Six rats were sacrificed at the end of reperfusion for determina-tion of myocardial infarct size. Another 6 rats were selected at the end of reperfusion and sacrificed for deter-mination of the level of creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH) in serum (by en-zyme-linked immunosorbent assay), expression of AMPK, phosphorylated AMPK ( p-AMPK), mTOR, phosphorylated mTOR (p-mTOR), ubiquitin-binding protein P62 (P62), microtubule-associated protein 1 light chain 3 Ⅰ(LC3 Ⅰ) and LC3Ⅱ in myocardial tissues (by Western blot). The ratios of p-AMPK∕AMPK, p-mTOR∕mTOR and LC3Ⅱ∕Ⅰwere calculated. Results Compared with group S, the myocardial infarct size and levels of serum CK-MB and LDH were significantly increased in I∕R, I∕R+MS and I∕R+M+CC groups, the ratios of p-AMPK∕AMPK and LC3Ⅱ∕Ⅰwere significantly increased, p-mTOR∕mTOR ratio was decreased, and P62 expression was down-regulated in group I∕R+MS (P＜0. 05), and no significant change was found in p-AMPK∕AMPK ratio, p-mTOR∕mTOR ratio, LC3Ⅱ∕Ⅰ ratio or P62 expression in I∕R and I∕R+M+CC groups (P＞0. 05). Compared with group I∕R, the myocardial infarct size and levels of serum CK-MB and LDH were significantly decreased, the ratios of p-AMPK∕AMPK and LC3Ⅱ∕Ⅰwere in-creased, p-mTOR∕mTOR ratio was decreased, and P62 expression was down-regulated in group I∕R+MS (P＜0. 05), and no significant change was found in the parameters mentioned above in group I∕R+M+CC (P＞0. 05). Compared with group I∕R+MS, the myocardial infarct size and levels of serum CK-MB and LDH were significantly increased, the ratios of p-AMPK∕AMPK and LC3Ⅱ∕Ⅰ were decreased, p-mTOR∕mTOR ratio was increased, and P62 expression was up-regulated in group I∕R+M+CC ( P＜0. 05). Con-clusion Class Ⅰ HDAC is involved in myocardial I∕R injury through enhancing AMPK∕mTOR signaling pathway-regulated level of autophagy in diabetic rats.