Abstract: Objective: To discuss the effect of Schizandrin B(Sch B) regulating miR- 22- 3p/runt- related transcription factor 3(RUNX3) molecular axis on injury of acinar cells with severe acute pancreatitis(SAP). Methods: The pancreatic acinar cells AR42J of rats were divided into the Con group,the SAP group,the SAP + Sch- L group,the SAP + Sch-M group,the SAP+Sch-H group,the SAP+anti-miR-NC group,the SAP+anti-miR-22-3p group,the SAP+Sch+miR-NC group,and the SAP+Sch+miR-22-3p group. Except for the Con group,the other groups were given caerulein at a dose of 10 nmol/L and lipopolysaccharide at a dose of 10 mg/L to stimulate AR42J cells for 24 hours to establish SAP cell model. In the SAP+Sch-L group,the SAP+Sch-M group,and the SAP+Sch-H group,the cells were treated with Sch B at concentrations of 10,20,and 40 μmol/L; in the SAP+anti-miR-NC group and the SAP+anti-miR-22-3p group,the cells were transfected with anti-miR-NC and anti-miR-22-3p respectively; in the SAP+Sch+miR-NC group and the SAP+ Sch+miR-22-3p group,the cells were transfected with miR-NC and miR-22-3p mimics respectively and intervened with Sch B at a concentration of 40 μmol/L. The expression levels of interleukin- 6(IL-6) and tumor necrosis factor α(TNF-α) in the culture supernatant of cells were detected by enzyme linked immunosorbent assay. The rate of cell apoptosis was detected by flow cytometry. The mRNA expression levels of miR- 22- 3p and RUNX3 were detected by real- time fluorescence quantitative PCR. The expression levels of RUNX3,B- cell lymphoma- 2(Bcl- 2),Bcl- 2- associated X protein (Bax),and cleaved-cysteinyl aspartate specific proteinase 3(cleaved-caspase3) were detected by BCA method. The targeted binding relationship between miR- 22- 3p and RUNX3 was detected by dual- luciferase reporter assay. Results:Compared with those in the Con group,in the SAP group,the expression levels of IL-6,TNF-α,miR-22-3p,Bax,and cleavedcaspase3 in AR42J cells as well as the rate of cell apoptosis were increased(P<0.05),and the expression levels of RUNX3 and Bcl- 2 were decreased(P<0.05). Compared with those in the SAP group, in the SAP + Sch- L group, SAP + Sch- M group and SAP+Sch-H group,the expression levels of IL-6,TNF- α,miR-22-3p and Bcl-2 were decreased(P<0.05), and the expression levels of Bax,cleaved- caspase3,and RUNX3 as well as the rate of cell apoptosis were increased(P< 0.05),and in a dose-dependent manner(P<0.05). Compared with those in the SAP+anti-miR-NC group,in the SAP+antimiR- 22-3p group,the expression levels of IL- 6,TNF-α,and Bcl-2 were decreased(P<0.05);the expression levels of Bax,cleaved-caspase3,and RUNX3 as well as the rate of cell apoptosis were increased(P<0.05). Compared with those in the SAP+Sch+miR-NC group,in the SAP+Sch+miR-22-3p group,the expression levels of IL-6,TNF-α,and Bcl-2 were increased(P<0.05);the expression levels of Bax,cleaved-caspase3,and RUNX3 as well as the rate of cell apoptosis were decreased(P<0.05). Conclusion:Sch B can relieve the injury of acinar cells with SAP by down-regulating miR-22-3p/RUNX3 molecular axis.