Objective To investigate the effect of miR-142-3p on the apoptosis of rat pancreatic exocrine cell line AR42J by regulating Hmgb1.Methods AR42J cells were divided into blank group(blank),acute pancreatitis model group(AP,100 nmol/L cerulein for 24 h),and then transfected with miR-142-3p mimics,mimics NC,miR-142-3p inhibitor and inhibitor NC,respectively.The cells in the model group were recorded as miR-142-3p mimics group,mimics NC group,miR-142-3p inhibitor group and inhibitor NC.The expression of miR-142-3p in cells was detected by RT-qPCR.The protein expressions of HMGB1,caspase-3,Bax and Bcl-2 were detected by Western blot.Hoechst staining was used to determine cell apoptosis.The apoptosis rate of cells was detected by flow cytometry.The targeting relationship between miR-142-3p and Hmgb1 was determined by dual luciferase reporter gene assay.Results Compared with blank control group,the expression level of miR-142-3p in the AP group was significantly down-regulated(P＜0.01),the expression level of HMGB1 and caspase-3 proteins was up-regulated(P＜0.05),the expression level of Bax protein was significantly up-regulated(P＜0.01),the expression level of Bcl-2 protein was significantly decreased(P＜0.01)and the apoptosis rate increased significantly(P＜0.01).Compared with the mimics NC group,the level of miR-142-3p in the miR-142-3p mimics group was significantly up-regulated(P＜0.01),the expression of HMGB,caspase-3 and Bax proteins was significantly down-regulated(P＜0.01),the expression of Bcl-2 protein was up-regulated(P＜0.05),and the apoptosis rate decreased signifi-cantly(P＜0.01).Compared with inhibitor NC group,the expression level of miR-142-3p in miR-142-3p inhibitor group was down-regulated(P＜0.05),the expression levels of HMGB1,caspase-3 and Bax proteins were signifi-cantly up-regulated(P＜0.01),the expression level of Bcl-2 protein was decreased(P＜0.05)and the apoptosis rate increased significantly(P＜0.01).The dual luciferase reporter gene assay showed that Hmgb1 was the target gene of miR-142-3p.Conclusions 1)The expression of miR-142-3p was low in the model group.2)miR-142-3p can inhibit the apoptosis of AR42J cells by inhibiting the expression of Hmgb1.