Objective:To investigate the mechanism of long non-coding RNA taurine up-regulated gene 1(lncRNA TUG1)in acute pancreatitis(AP).Methods:The mouse pancreatic acinar cell line(MPC-83)was cultured in vitro,and treated with lipopoly-saccharide(LPS,10 μg/ml)and cerulein(Caerulein,100 nmol/L)for 3 h to establish the AP model.The experiment was divided into control group,AP group,AP+sh-NC group,AP+sh-TUG1 group,AP+sh-TUG1+inhibitor-NC group,and AP+sh-TUG1+miR-31-5p inhibitor group.Quantitative real-time PCR(qRT-PCR)was performed to measure the expression levels of lncRNA TUG1 and miR-31-5p in cells;CCK-8 method was performed to measure cell viability;flow cytometry was performed to measure apoptosis;ELISA was performed to measure the levels of IL-1β and tumor necrosis factor α(TNF-α)in the cell supernatant;and dual-luciferase reporter gene experiments was performed to verify the targeting relationship between lncRNA TUG1 and miR-31-5p.The AP mouse model was constructed,and after corresponding intervention,qRT-PCR was performed to determine the lncRNA TUG1 and miR-31-5p expres-sion levels in pancreatic tissue;the serum inflammatory factors IL-1β,TNF-α contents and amylase(AMY)and lipase(Lipase)activities were determined by kits;HE staining was performed to observe histopathological changes of pancreas;TUNEL was per-formed to detect apoptosis in pancreatic tissue.Results:In MPC-83 cells co-treated with Caerulein and LPS,the lncRNA TUG1 level,apoptosis rate,IL-1β and TNF-α levels were increased,while miR-31-5p level and cell viability were decreased(all P<0.05);knock-down of lncRNA TUG1 up-regulated miR-31-5p,increased cell viability,decreased IL-1β and TNF-α levels,and inhibited cell apop-tosis(all P<0.05);down-regulation of miR-31-5p expression attenuated the inhibitory effect of lncRNA TUG1 knockdown on cellular inflammatory responses.miR-31-5p was a direct target of lncRNA TUG1.Knockdown of lncRNA TUG1 expression in vivo was able to up-regulate the expression of miR-31-5p in pancreatic tissue of AP mice,reduce the levels of IL-1β and TNF-α,reduce cell apoptosis,and improve pancreatic tissue damage.Conclusion:Knockdown of lncRNA TUG1 may improve AP by up-regulating the expression level of miR-31-5p and inhibiting the inflammatory response.