ObjectiveTo investigate the effects of Toll-like receptor 4 （TLR4） inhibition on autophagy and oxidative stress， as well as its regulatory role and mechanism in the inflammatory response in a mouse model of gastric ulcer. MethodsSixty adult male Kunming mice were equally divided into five groups： control group， model group， model+TLR4-IN-C34 group， model+TLR4-IN-C34+3-MA group， and model+TLR4-IN-C34+H₂O₂ group. Except for the control group， all groups were administered 40 mg/kg indomethacin via gavage. Treatment groups received injections every three days， and all groups were treated for 30 days. Mice were euthanized by cervical dislocation， and gastric tissues were collected. Gastric ulcer scores were assessed， and pathological changes were evaluated via HE staining and scoring. Serum levels of interleukin-1β （IL-1β）， IL-6， tumor necrosis factor-α （TNF-α）， advanced oxidation protein products （AOPP）， and prostaglandin E2 （PGE2）， as well as gastric tissue levels of malondialdehyde （MDA）， superoxide dismutase （SOD）， and reduced glutathione （GSH）， were measured using ELISA. Western blot analysis was performed to detect the expression of TLR4， microtubule-associated protein 1 light chain 3-Ⅰ （LC3-Ⅰ），LC3-Ⅱ， autophagy-related protein 5 （Atg5）， Beclin-1， nuclear factor erythroid 2-related factor 2 （Nrf2）， heme oxygenase-1 （HO-1）， and NAD（P）H quinone dehydrogenase 1 （NQO1） in gastric tissues. Immunofluorescence staining was used to assess LC3-Ⅱ fluorescence intensity in gastric tissues. ResultsCompared with the control group， the model group exhibited upregulation of ulcer scores， HE staining scores， TLR4， IL-1β， IL-6， TNF-α， and AOPP levels， and downregulation of LC3-Ⅱ fluorescence intensity， PGE2 levels， Atg5， Beclin-1， nuclear Nrf2， HO-1， NQO1 levels， and the LC3-Ⅱ/Ⅰ ratio （all P < 0.05）. Compared with the model group， the model+TLR4-IN-C34 group showed downregulation of ulcer scores， HE staining scores， TLR4， IL-1β， IL-6， TNF-α， and AOPP levels， and upregulation of LC3-Ⅱ fluorescence intensity， PGE2 levels， Atg5， Beclin-1， nuclear Nrf2， HO-1， NQO1 levels， and the LC3-Ⅱ/Ⅰ ratio （all P < 0.05）. Compared with the model+TLR4-IN-C34 group， the model+TLR4-IN-C34+3-MA group exhibited upregulation of ulcer scores， HE staining scores， IL-1β， IL-6， TNF-α， and AOPP levels， and downregulation of LC3-Ⅱ fluorescence intensity， PGE2 levels， Atg5， Beclin-1， and the LC3-Ⅱ/Ⅰ ratio （all P < 0.05）. Compared with the model+TLR4-IN-C34 group， the model+TLR4-IN-C34+H₂O₂ group showed upregulation of ulcer scores， HE staining scores， IL-1β， IL-6， TNF-α， and AOPP levels， and downregulation of PGE2 levels and nuclear Nrf2， HO-1， and NQO1 levels （all P < 0.05）. ConclusionInhibition of TLR4 ameliorates gastric ulcer symptoms and suppresses the inflammatory response in mice by upregulating autophagy and reducing oxidative stress.