Background and Purpose Pyroptosis is a lytic form of pro‐inflammatory cell death characterised as caspase 1 dependent with canonical NLRP3 inflammasome‐induced gasdermin D (GSDMD) activation. We aimed to investigate the role of acinar pyroptotic cell death in pancreatic injury and systemic inflammation in AP. Experimental Approach Pancreatic acinar pyroptotic cell death pathway activation upon pancreatic toxin stimulation in vitro and in vivo was investigated. Effects of pharmacological (NLRP3 and caspase‐1 inhibitors), constitutive (Nlrp3−/−, Casp1−/− and Gsdmd−/−) and acinar cell conditional (Pdx1CreNlrp3Δ/Δ and Pdx1CreGsdmdΔ/Δ) genetic inhibition on pyroptotic acinar cell death, pancreatic necrosis and systemic inflammation were assessed using mouse AP models (caerulein, sodium taurocholate and l‐arginine). Effects of Pdx1CreGsdmdΔ/Δ versus myeloid conditional knockout (Lyz2CreGsdmdΔ/Δ) and Gsdmd−/− versus receptor‐interacting protein 3 (RIP3) inhibitor were compared in CER‐AP. Key Results There was consistent pyroptotic acinar cell death upon pancreatic toxin stimulation both in vitro and in vivo, which was significantly reduced by pharmacological or genetic pyroptosis inhibition. Pdx1CreGsdmdΔ/Δ but not Lyz2CreGsdmdΔ/Δ mice showed significantly reduced pyroptotic acinar cell death, pancreatic necrosis and systemic inflammation in caerulein‐AP. Co‐application of RIP3 inhibitor on Gsdmd−/− mice further increased protection on caerulein‐AP. Conclusion and Implications This work demonstrates a critical role for NLRP3 inflammasome and GSDMD activation‐mediated pyroptosis in acinar cells, linking pancreatic necrosis and systemic inflammation in AP. Targeting pyroptosis signalling pathways holds promise for specific AP therapy.

Background. Danshen (Salvia miltiorrhiza Bunge) and its main active component Tanshinone IIA (TSA) are clinically used in China. However, the effects of TSA on acute pancreatitis (AP) and its potential mechanism have not been investigated. In this study, our objective was to investigate the protective effects of TSA against AP via three classic mouse models. Methods. Mouse models of AP were established by caerulein, sodium taurocholate, and L-arginine, separately. Pancreatic and pulmonary histopathological characteristics and serum amylase and lipase levels were evaluated, and changes in oxidative stress injury and the ultrastructure of acinar cells were observed. The reactive oxygen species (ROS) inhibitor N-Acetylcysteine (NAC) and nuclear factor erythroid 2-related factor 2 (Nrf2) knockout mice were applied to clarify the protective mechanism of the drug. Results. In the caerulein-induced AP model, TSA administration reduced serum amylase and lipase levels and ameliorated the histopathological manifestations of AP in pancreatic tissue. Additionally, TSA appreciably decreased ROS release, protected the structures of mitochondria and the endoplasmic reticulum, and increased the protein expression of Nrf2 and heme oxygenase 1 of pancreatic tissue. In addition, the protective effects of TSA against AP were counteracted by blocking the oxidative stress (NAC administration and Nrf2 knockout in mice). Furthermore, we found that TSA protects pancreatic tissue from damage and pancreatitis-associated lung injury in two additional mouse models induced by sodium taurocholate and by L-arginine. Conclusion. Our data confirmed the protective effects of TSA against AP in mice by inhibiting oxidative stress via the Nrf2/ROS pathway.