Glycyrrhizin Ameliorates Cardiac Injury in Rats with Severe Acute Pancreatitis by Inhibiting Ferroptosis via the Keap1/Nrf2/HO-1 Pathway.

Severe acute pancreatitis (SAP) is a potential fatal gastrointestinal disease that is usually complicated by myocardial injury and dysfunction. Due to the lack of understanding of the mechanism of SAP-associated cardiac injury (SACI), there is still no complete treatment. To explore the alleviative effect and anti-ferroptosis mechanism against SACI of glycyrrhizin (GL), an inhibitor of oxidative stress. The SAP model was established by perfusing 5% sodium taurocholate into biliopancreatic duct in rats. H&E staining and serum assays were used to assess the injury changes of pancreas and heart. Echocardiography was used to evaluate the cardiac function. Transmission electron microscopy (TEM) and oxidative stress assays were used to investigate the ferroptosis-related morphological and biochemical changes. Western blot and immunofluorescence were performed to analyzed the expression of ferroptosis-related proteins. Significant myocardial impairment was found in SAP rats according to increased histopathological scores, serum creatine kinase-MB (CK-MB) and cardiac troponin-I (cTnI) levels, and a decreased fractional shortening and ejection fraction. The decreased mitochondrial cristae and significant expression changes of ferroptosis-related proteins confirmed the presence of ferroptosis in SACI. GL treatment attenuated above-mentioned cardiac tissues damage by inhibiting ferroptosis via restoring the expression of Nrf2 and HO-1 in vivo and in vitro. Treating with ML385 (a Nrf2 inhibitor) or transfecting with siRNA-Nrf2 reversed the protective effect of GL. Our findings demonstrate the involvement of ferroptosis in SACI and suggest a potential role for GL in the treatment of SACI by supressing ferroptosis via Keap1/Nrf2/HO-1 pathway.

Cui Q ，Wang W ，Shi J ，Lai F ，Luo S ，Du Y ，Wang X ，Xiang Y ... -  《-》

Emodin protects against severe acute pancreatitis-associated acute lung injury by activating Nrf2/HO-1/GPX4 signal and inhibiting ferroptosis in vivo and in vitro.

Severe acute pancreatitis (SAP) has high morbidity, a complicated and dangerous course, and many complications, including severe pulmonary complications. SAP-associated acute lung injury (SAP-ALI) is still a significant challenge for surgeons because of its high mortality. Therefore, more effective treatment methods are urgently needed. Emodin (EMO) has shown tremendous potential in treating many refractory diseases. However, its protection mechanism in SAP-ALI needs to be further clarified. This study was undertaken to investigate the protective effects of EMO against lung injury in SAP rats and alveolar epithelial cells, with a particular focus on the classical ferroptosis pathway. In an in vivo study, forty SD rats were evenly split into five groups: sham operation (SO) group, the biliopancreatic duct was retrogradely injected with 5% sodium taurocholate (STC) to create the SAP group, SAP + EMO group was administered EMO via gavage to the rats following the modeling, SAP + ML385 group (a given inhibitor of nuclear factor erythroid 2-related factor 2 (Nrf2)), SAP + ML385 + EMO group. In an in vitro study, alveolar epithelial A549 cell lines were exposed to lipopolysaccharide (LPS) and treated with EMO. ML385 was also used to inhibit the expression of Nrf2. Pancreatic and lung tissue damage was evaluated using histological examination and molecular experiments. Enzyme-linked immunosorbent assays (ELISA) were used to assess the levels of pro-inflammatory cytokines, Fe2+, and associated oxidative stress indicators in the serum and cell supernatant. Real-time polymerase chain reaction (PCR), Western blot (WB), and immunofluorescence were used to find the expressions of related mRNAs and proteins in the lung tissue or A549 cells. The findings demonstrated that suppressing Nrf2 expression exacerbated the inflammatory response brought on by SAP and the pathological alterations of SAP-ALI. Emodin treatment reversed this pathological change by activating the Nrf2/Heme Oxygenase-1 (HO-1)/glutathione peroxidase 4 (GPX4) signal path. Moreover, these results also showed that EMO, contrary to the effects of ML385, suppressed the ferroptosis response, which manifested as up-regulated glutathione (GSH) and GPX4 levels in vivo and in vitro and down-regulated malondialdehyde (MDA), superoxide dismutase (SOD), Fe2+, and reactive oxygen species (ROS) levels. Our results demonstrated that EMO effectively inhibited ferroptosis both in vivo and in vitro, while also modulating the Nrf2/HO-1/GPX4 signaling pathway to provide protection against SAP-ALI.

Shen G ，Wen H ，Li H ，Zhang X ，Lan B ，Dong X ，Ge P ，Luo Y ，Chen H ... -  《BMC GASTROENTEROLOGY》

Bufalin alleviates inflammatory response and oxidative stress in experimental severe acute pancreatitis through activating Keap1-Nrf2/HO-1 and inhibiting NF-κB pathways.

Severe acute pancreatitis (SAP) is a prevalent acute inflammatory disease that is clinically manifested by systemic inflammation dysregulation, resulting in a significantly elevated mortality rate. Bufalin has been verified to have potent pharmacological properties, including analgesic, anti-tumor and anti-inflammatory effects. However, it remains unclear whether bufalin inhibits SAP. Thus, we aim to explore the impact of bufalin in SAP rats and to evaluate the potential mechanisms of action. In addition to analyzing serum biochemistry and pancreatic tissue pathology, we elucidated its mechanisms of action through enzyme-linked immunosorbent assay (ELISA), immunohistochemical analysis, Western blot, and quantitative real-time PCR. The results demonstrated that bufalin dose-dependently reversed the elevation of serum Amylase (Amy) and Lipase (LPS) levels in SAP rats, alleviating pancreatic tissue pathological damage. Bufalin exhibited potent antioxidant effects by reducing malondialdehyde (MDA) levels, decreasing Superoxide dismutase (SOD) and glutathione(GSH) consumption, inhibiting the interaction of Keap1-Nrf2, and increasing HO-1 expression. Furthermore, bufalin inhibited TNF-α, IL-6, IL-1β, p-NF-κB-p65, p-IκBα, and NF-κB-p65 expression, while enhancing IκBα expression, ultimately confirming its anti-inflammatory effects on SAP. In summary, our findings suggest that bufalin exerts anti-inflammatory and antioxidant actions in NaT-SAP rats by inhibiting NF-κB and activating the Keap1-Nrf2/HO-1 pathway. This study represents the inaugural application of bufalin in NaT-induced SAP rats, indicating its potential as an effective therapeutic agent for SAP patients.

Niu X ，Sun W ，Tang X ，Chen J ，Zheng H ，Yang G ，Yao G ... -  《-》

The main active components of Prunella vulgaris L. alleviate myocardial ischemia-reperfusion injury by inhibiting oxidative stress and ferroptosis via the NRF2/GPX4 pathway.

Prunella vulgaris L. (PV) is a widely distributed medicinal and edible plant used in traditional Chinese medicine for its anti-tumor, anti-inflammatory, anti-oxidant, hypoglycemic, and anti-hypertensive effects. Despite the numerous studies reporting on its cardiovascular protective effects, it is still unknown whether PV could relieve myocardial ischemia-reperfusion (MI/R) injury. To investigate the effects of PV on MI/R injury and explore the underlying mechanism of action. Sprague-Dawley rats were orally administrated with the aqueous extract of P. vulgaris for 7 days before MI/R injury was induced. Echocardiography, infarct staining, and TUNEL assay were used to evaluate the protective effect of P. vulgaris. H2O2- and RSL3-stimulated H9C2 rat myocardial cells were used to explore the underlying mechanism. Ultra-high-performance liquid chromatography/mass spectrometer analysis was used to identify the chemical constituents of P. vulgaris. AutoDock software was used to predict the binding affinity and the interactions between the main active compounds and Keap1. Nuclear factor erythroid 2-related factor 2 (Nrf2) knock-out mice were used to confirm whether the protective effect of P. vulgaris was mediated by Nrf2. P. vulgaris improved left ventricular systolic function and decreased the myocardial infarct area, which alleviated the MI/R injury. PV also increased the level of Nrf2 proteins and promoted the expression of HO-1, SOD, and GSH, thus upregulating the activity of the antioxidant system. The molecular docking simulations indicated that rosmarinic acid, salviaflaside, ursolic acid, and protocatechuic acid from P. vulgaris could strongly bind to Keap1 protein with good binding affinities. Additionally, ursolic acid was found to elevate NRF2 protein levels and promote NRF2 nuclear translocation. Moreover, the cardiac protective effect of PV or ursolic acid disappeared in NRF2-/- mice, indicating that this protective effect was mediated by NRF2. Also, PV increased the protein levels of GPX4 in MI/R rat or mice models, and this upregulation disappeared in NRF2-/- mice. Results from the RSL-3-induced ferroptosis H9C2 cell model showed that ursolic acid was the main active component of PV that protects cardiomyocytes against ferroptosis. Collectively, the findings indicate that PV could alleviate MI/R injury by inhibiting oxidative stress and ferroptosis via the NRF2/GPX4 pathway, and ursolic acid is the main active component responsible for mediating both antioxidative and anti-ferroptosis effects, suggesting its potential use as a therapeutic agent against MI/R injury.

Leng L ，Li P ，Liu R ，Francis OB ，Song S ，Sui Y ，Yang Y ，Wang Y ，Sun X ，Miao R ，Yuan Q ，Li X ，Yang W ，Gao X ，Wang Q ... -  《-》

Glycyrrhizic acid alleviates the meconium-induced acute lung injury in neonatal rats by inhibiting oxidative stress through mediating the Keap1/Nrf2/HO-1 signal pathway.

Zhu L ，Wei M ，Yang N ，Li X ... -  《-》