OBJECTIVE To investigate the effects and potential mechanism of paeoniflorin on oxidative stress of ulcerative colitis （UC） mice based on adenosine monophosphate-activated protein kinase （AMPK）/nuclear factor-erythroid 2-related factor 2 （Nrf2） pathway. METHODS Male BALB/c mice were randomly divided into control group， model group， inhibitor group （AMPK inhibitor Compound C 20 mg/kg）， paeoniflorin low-， medium- and high-dose groups （paeoniflorin 12.5， 25， 50 mg/kg）， high- dose of paeoniflorin+inhibitor group （paeoniflorin 50 mg/kg+Compound C 20 mg/kg）， with 8 mice in each group. Except for the control group， mice in all other groups were given 4% dextran sulfate sodium solution for 5 days to establish the UC model. Subsequently， mice in each drug group were given the corresponding drug solution intragastrically or intraperitoneally， once a day， for 7 consecutive days. The changes in body weight of mice were recorded during the experiment. Twenty-four hours after the last administration， colon length， malondialdehyde （MDA） content， and activities of superoxide dismutase （SOD） and glutathione peroxidase （GSH-Px） in colon tissues were measured； histopathological morphology of colon tissues， tight junctions between intestinal epithelial cells， and histopathological scoring were all observed and evaluated； the mRNA expressions of AMPK and Nrf2， as well as the protein expressions of heme oxygenase-1（HO-1）， occludin and claudin-1， were all determined in colon tissue. RESULTS Compared with model group， paeoniflorin groups exhibited recovery from pathological changes such as inflammatory cell infiltration and crypt damage in the colon tissue， as well as improved tight junction damage between intestinal epithelial cells. Additionally， significant increases or upregulations were observed in body weight， colon length， activities of SOD and GSH-Px， phosphorylation level of AMPK， and protein expression of Nrf2， HO-1， occludin， claudin-1， and mRNA expressions of AMPK and Nrf2； concurrently， MDA content and histopathological scores were significantly reduced （P＜ 0.05 or P＜0.01）. In contrast， the inhibitor group showed comparable （P＞0.05） or worse （P＜0.05 or P＜0.01） indicators compared to the model group. Conversely， the addition of AMPK inhibitor could significantly reverse the improvement of high- dose paconiflorin （P＜0.01）. CONCLUSIONS Paeoniflorin can repair intestinal epithelial cell damage in mice， improve tight junctions between epithelial cells， upregulate the expression of related proteins， and promote the expression and secretion of antioxidant-promoting molecules， thereby ameliorating UC； its mechanism may be associated with activating AMPK/Nrf2 antioxidant pathway.

ObjectiveTo explore the mechanism of Huanglian Jiedutang in inhibiting the pyroptosis mediated by NOD-like receptor protein 3 （NLRP3） inflammasomes and alleviating the acute liver injury （ALI） induced by lipopolysaccharide （LPS） in the mouse model of sepsis. MethodFifty-four male C57BL/6 mice were randomized into blank， model， low- （3.08 g·kg^-1）， medium- （6.15 g·kg^-1）， and high-dose （12.30 g·kg^-1） Huanglian Jiedutang， and positive control （dexamethasone） groups （n=9）. The mice were administrated with Huanglian Jiedutang at different doses by gavage for 7 days， and then LPS （15 mg·kg^-1） was injected intraperitoneally for the modeling of sepsis. In the positive control group， dexamethasone （0.05 g·kg^-1） was injected intraperitoneally 1.5 h after modeling， and the mouse sepsis score （MSS） was recorded 12 h after modeling. The mice were sacrificed for the collection of blood and liver tissue samples. The levels of alanine transaminase （ALT） and aspartate transaminase （AST） were measured by a biochemical analyzer. The levels of tumor necrosis factor （TNF）-α， interleukin （IL）-6， IL-1β， and IL-18 in the serum were measured by enzyme-linked immunosorbent assay kits. Hematoxylin-eosin staining was used to observe the pathological changes in the liver tissue. The content of NLRP3 was observed by the immunofluorescence assay. The expression of apoptosis-associated speck-like protein containing CARD （ASC） was detected by immunohistochemistry. The protein levels of NLRP3， ASC， Caspase-1， and gasdermin D （GSDMD） in the liver tissue were determined by Western blot. Real-time quantitative polymerase chain reaction（Real-time PCR） was employed to determine the mRNA levels of GSDMD， Caspase-1， IL-1β， and IL-18. ResultCompared with the blank group， the model group showed elevated levels of ALT and AST （P<0.01） and risen levels of inflammatory cytokines in the serum （P<0.01）. In addition， the modeling resulted in edema and necrosis in the liver， and up-regulated the protein levels of GSDMD， NLRP3， ASC， and Caspase-1 （P<0.01） and the mRNA levels of GSDMD， Caspase-1， IL-1β， and IL-18 （P<0.01）. Compared with the model group， the drug intervention groups showed reduced content of inflammatory cytokines （P<0.01）， alleviated pathological damage in the liver tissue， and down-regulated protein levels of GSDMD， NLRP3， ASC， and Caspase-1 （P<0.05，P<0.01） and mRNA levels of GSDMD， Caspase-1， IL-1β， and IL-18 （P<0.05，P<0.01） in the liver tissue. ConclusionHuanglian Jiedutang can inhibit pyroptosis and reduce inflammation by inhibiting the activation of NLRP3 inflammasomes， thus demonstrating a therapeutic effect on acute liver injury in the mouse model of sepsis induced by LPS.