Estrogen alleviates myocardial ischemia-reperfusion injury by inhibiting NLRP3 inflammasome -mediated pyroptosis

Abstract The present study was designed to investigate whether 17β-estrogen (E2) reduces myocardial I/R injury by inhibiting NLRP3 inflammasome mediated pyroptosis. In vivo, four-weeks-old female C57BL/6 mice underwent ovariectomy (Ovx) before E2 replacement therapy. After the establishment of myocardial I/R injury, plasma E2, LDH and CK-MB were detected, and the myocardial infarction (MI) size, TUNEL immunofluorescence, and the expressions of TXNIP, NLRP3, caspase-1, apoptosis-associated speck-like protein containing a CARD (ASC), Gasdermin D protein (GSDMD), IL-1β were compared among each group. In vitro, primary mice cardiomyocytes were isolated to create hypoxia/reoxygenation (H/R) model. The cells viability, the release of LDH, TXNIP, IL-18, IL-1β, caspase-1 viability, level of cardiomyocytes death and the expression of TXNIP, NLRP3, caspase1, ASC, IL-1β, GSDMD were compared among each groups. In vivo, E2 replacement therapy significantly reduced infarct size and pyroptosis compared with mice in OVX + I/R group. In addition, E2 replacement could markedly suppressed expressions of pyroptosis related proteins, including TXNIP, NLRP3, cleaved Caspase-1, ASC, IL-1β as well as the pyroptosis executor GSDMD. In vitro, the effects of E2 on cardiomyocytes injury and pyroptosis related proteins were dramatically reversed when co-administrated with estrogen receptor antagonist ICI 182780. In addition, NLRP3 inhibitor Bay11-7082 could preserve cell viability, reduce pyroptosis as well as expressions of pyroptosis related proteins. Furthermore, pretreatment with Caspase-1 inhibitor AC-YVAD-CMK could significantly limit cell injury and reduce expressions of pyroptosis related proteins. Our study demonstrated that estrogen alleviate myocardial I/R injury by inhibiting the level of pyroptosis via ER/TXNIP/NLRP3/Caspase-1.