Role of Rev-erbα/Bmal1 signaling pathway in myocardial ischemia-reperfusion injury and relationship with autophagy in diabetic rats / 中华麻醉学杂志

ABSTRACT

Objective:To evaluate the role of nuclear receptor subfamily 1, group D, member 1/brain and muscle Arnt-like 1(Rev-erbα/Bmal1) signaling pathway in myocardial ischemia-reperfusion (I/R) injury in diabetic rats and its relationship with autophagy.Methods:SPF-grade adult male Sprague-Dawley rats, aged 6-8 weeks, weighing 200-220 g, were used in this study.Type I diabetes mellitus was induced by intraperitoneal streptozotocin 60 mg/kg.The rats were continuously fed for 8 weeks after successful establishment of the model.Thirty rats with type 1 diabetes mellitus were divided into 3 groups by a random number table method: diabetic sham operation group (DS group, n=6), diabetic myocardial I/R group (DI/R group, n=12) and diabetic myocardial I/R plus Rev-erbα antagonist SR-8278 group (DI/R+ SR group, n=12). Eighteen non-diabetic rats were divided into 2 groups by a random number table method: non-diabetic sham operation group (NS group, n=6) and non-diabetic myocardial I/R group (NI/R group, n=12). The myocardial I/R model was established by ligation of the left anterior descending coronary artery for 30 min followed by 120-min reperfusion in anesthetized rats.SR-8278 2 mg/kg was intravenously injected via the femoral vein at 1 h before ischemia in group DI/R+ SR.Blood samples were collected from the carotid artery immediately after the end of reperfusion for determination of serum troponin I (cTnI), creatine kinase-MB (CK-MB) and lactic dehydrogenase (LDH) levels (by enzyme-linked immunosorbent assay). Then the rats were sacrificed, and myocardial tissues were obtained for determination of myocardial infarct size (by TTC method), expression of Rev-erbα and Bmal1 mRNA (by real-time polymerase chain reaction) and expression of Rev-erbα, Bmal1, microtubule-associated protein 1 light chain (LC3) Ⅱ and LC3Ⅰ (by Western blot) and for calculation of the ratio of LC3 Ⅱ/LC3Ⅰand the number of autophagosomes (with a transmission electron microscope). Results:Compared with group NS, the percentage of myocardial infarct size, serum levels of cTnI, CK-MB and LDH and the number of autophagosomes were significantly increased, the expression of Rev-erbα and its mRNA in myocardial tissues was up-regulated, the expression of Bmall and its mRNA was down-regulated, and the ratio of LC3 Ⅱ/LC3Ⅰwas increased in group NI/R, and serum levels of cTnI, CK-MB and LDH were increased, the number of autophagosomes was decreased, the expression of Rev-erbα and its mRNA in myocardial tissues was up-regulated, the expression of Bmall and its mRNA was down-regulated and the ratio of LC3 Ⅱ/LC3Ⅰwas decreased in group DS ( P<0.05). Compared with group NI/R, the percentage of myocardial infarct size and serum levels of cTnI, CK-MB and LDH were significantly increased, the number of autophagosomes was decreased, the expression of Rev-erbα and its mRNA in myocardial tissues was up-regulated, the expression of Bmall and its mRNA was down-regulated, and the ratio of LC3 Ⅱ/LC3Ⅰwas decreased in group DI/R ( P<0.05). Compared with group DS, the percentage of myocardial infarct size, serum levels of cTnI, CK-MB and LDH and the number of autophagosomes were were significantly increased, the expression of Rev-erbα and its mRNA in myocardial tissues was up-regulated, the expression of Bmall and its mRNA was down-regulated, and the ratio of LC3 Ⅱ/LC3Ⅰwas increased in group DI/R ( P<0.05). Compared with group DI/R, the percentage of myocardial infarct size, serum levels of cTnI, CK-MB and LDH and the number of autophagosomes were significantly decreased, the expression of Rev-erbα and its mRNA in myocardial tissues was down-regulated, the expression of Bmall and its mRNA was up-regulated, and the ratio of LC3 Ⅱ/LC3Ⅰwas increased in group DI/R+ SR ( P<0.05). Conclusion:Rev-erbα/BMAL1 signaling pathway is involved in the process of myocardial I/R injury by regulating cell autophagy in diabetic rats.