Inhibition of the NLRP3 inflammasome limits the inflammatory injury following myocardial ischemia–reperfusion in the mouse

Abstract Background Successful reperfusion is the most effective strategy to reduce ischemic injury in acute myocardial infarction (AMI). Ischemic injury, however, also triggers a secondary ischemia–independent injury, known as reperfusion injury, contributing to the overall infarct size. We hypothesize that inhibition of the Nod-like Receptor Protein-3 (NLRP3) inflammasome limits infarct size following myocardial ischemia/reperfusion (I/R), by inhibiting the inflammatory component of the reperfusion injury. Methods CD-1 male mice underwent transient ligation of the left anterior descending coronary artery for 30 or 75 min followed by reperfusion. Infarct size was measured at 1, 3 and 24 h. A NLRP3 inflammasome inhibitor (NLRP3inh) or vehicle was administrated immediately at time of reperfusion or with a delay of 1 or 3 h of reperfusion. Results A time-dependent increase in infarct size was measured at 1, 3, and 24 h after reperfusion (11 ± 2%, 30 ± 5% and 43 ± 4% of the area at risk respectively; P < 0.001 for trend). NLRP3 myocardial expression was significantly increased at 24 h and 6 h vs 3 h (P < 0.01). Administration of the NLRP3inh at reperfusion did not reduce infarct size at 3 h, while it significantly reduced infarct size at 24 h (− 56% vs vehicle, P < 0.01). The NLRP3inh given 1 h after reperfusion also significantly decreased caspase-1 activity and infarct size measured at 24 h, whereas the NLRP3inh did not when given with a delay of 3 h. Conclusions Pharmacological inhibition of the NLRP3 inflammasome within 1 h of reperfusion limits the secondary inflammatory injury and infarct size following myocardial ischemia–reperfusion in the mouse.