Role of NLRP3 inflammasome in pyroptosis during myocardial ischemia-reperfusion in diabetic rats / 中华麻醉学杂志

ABSTRACT

Objective To evaluate the role of NOD-like receptor 3 (NLRP3) inflammasome in pyroptosis during myocardial ischemia-reperfusion (I/R) in diabetic rats.Methods SPF male Sprague-Dawley rats,aged 6-8 weeks,weighing 210-230 g,were studied.Type 1 diabetes mellitus (DM) was induced by intraperitoneal injection of 1％ streptozotocin 60 mg/kg.Forty-two rats with type 1 DM were divided into 4 groups using a random number table method:sham operation group (DS group,n =6),myocardial I/R group (DI/R group,n =12),myocardial I/R plus caspase-1 inhibitor Ac-YVAD-CMK group (DI/R+Ac group,n=12) and myocardial I/R plus NLRP3 inhibitor BAY11-7082 group (DI/R+BAY group,n=12).Eighteen healthy adult male Sprague-Dawley rats were selected and randomly divided into sham operation group (group S,n =6) and myocardial I/R group (group I/R,n =12).Myocardial I/R was induced by 30 min occlusion of the left anterior descending branch of the coronary artery followed by 120 min reperfusion at 8 weeks after successful establishment of the type 1 DM model.Ac-YVAD-CMK 1.5 mg/kg and BAY1 1-7082 5 mg/kg were intraperitoneally injected at 10 min before reperfusion in DI/R+Ac group and DI/R+BAY group,respectively.At the end of reperfusion,the myocardial infarct size was measured using TTC staining,the activities of creatine kinase-MB (CK-MB) and lactate dehydrogenase (LDH) in serum were detected by enzyme-linked immunosorbent assay,the ultrastructure of myocardium was observed by transmission electron microscopy,and the expression of NLRP3,pro-caspase-1,caspase-1,apoptosis-associated speck-like protein containing CARD (ASC) and interleukin-1 (IL-1β) in myocardial tissues was detected by Western blot.Results Compared with group S or group DS,the activities of serum CK-MB and LDH were significantly increased,and the expression of NLRP3,pro-caspase-1,caspase-1,ASC and IL-1β was down-regulated in I/R and DI/R groups (P＜0.05).Compared with group DI/R,the percentage of myocardial infarct size and activities of serum CK-MB and LDH were significantly decreased,and the expression of NLRP3,pro-caspase-1,caspase-1,ASC and IL-1β was down-regulated in group I/R,the percentage of myocardial infarct size and activities of serum CK-MB and LDH were significantly decreased,and the expression of pro-caspase-1,ASC and IL-1 β was down-regulated in group DI/R+Ac,and the percentage of myocardial infarct size and activities of serum CK-MB and LDH were significantly decreased,and the expression of NLRP3,pro-caspase-1,caspase-1,ASC and IL-1β was down-regulated (P＜0.05),and the pathological changes of myocardium were significantly attenuated in group DI/R+BAY.Conclusion The mechanism of pyroptosis during myocardial I/R may be related to the activation of NLRP3 inflammasome in diabetic rats.